On the morning of Oct. 21, Alec Baldwin had an epiphany.

Sitting in a church pew on the set of “Rust,” a low-budget Western film, the star actor observed the hustle-and-bustle around him with a renewed sense of appreciation. A project he loved was finally coming to life – the magic of the cinema felt within reach.

“I sat on that bench, and I said, ‘This movie has made me love making movies again,’” Baldwin told ABC News’ George Stephanopoulos in his first exclusive interview.

“I really thought we were onto something,” he continued. “And then this gun goes off.”

Hours after his moment of reflection, Baldwin was holding an antique Colt .45 revolver during a marking rehearsal for the film, when the prop gun discharged a live bullet, killing cinematographer Halyna Hutchins and wounding director Joel Souza.

“Someone put a live bullet in a gun, a bullet that wasn’t even supposed to be on the property,” Baldwin said. “Someone is ​responsible for what happened, and I can’t say who that is, but I know it’s not me.”

Baldwin sat down with Stephanopoulos to sift through the series of events that led to Hutchins’ death, saying he had no reason to suspect a live bullet could be in the prop gun. He also discussed the criticism, litigation and investigations surrounding the ​incident.

“I don’t know what happened on that set. I don’t know how that bullet arrived in that gun. I don’t know,” Baldwin said. “But I’m all for doing anything that will take us to a place where this is less likely to happen again.”

“Alec Baldwin Unscripted,” produced by George Stephanopoulos Productions, airs in a one-hour primetime special event on Thursday 8 p.m. ET/7 p.m. CT on ABC and streams on Hulu later that evening.

Next week, a two-hour “20/20” delves into the events ahead of the deadly shooting on the set of “Rust” and the pending investigations into what went wrong, and features the Baldwin interview and new interviews. “20/20” airs Friday, Dec. 10 (9:01–11:00 p.m. EST), on ABC and streaming next day on Hulu.

‘A cold gun’

The cast and crew of “Rust” were working against the clock, Baldwin said. The budget, approximately $7 million, accounted for just 21 days of filming at the famed Bonanza Ranch in Santa Fe, New Mexico.

The film’s producers were excited to have secured Hutchins, a 41-year-old mother and a rising star in the notoriously competitive industry. Baldwin and Hutchins had never worked together before.

“I loved working with this woman,” he said. “She was a joy. Everyone loved her as a person. And everyone admired her talent.”

On the day of the shooting, Baldwin said he and Hutchins met to discuss an upcoming scene. In it, Baldwin was playing a cornered and badly wounded character who would draw his weapon on two foes.

During rehearsal, Baldwin said the film’s first assistant director, Dave Halls, handed him a revolver. Baldwin recalled Halls telling him, “This is a cold gun” – industry jargon for a weapon that is either literally empty or loaded with non-firing “dummy” rounds.

“Now, what happened there, and why he made that statement, and what the realities were, I have, again, I have no idea,” Baldwin said.

Lisa Torraco, a lawyer for Halls, has since said that checking the weapon was “not his responsibility,” and that “expecting an assistant director to check a firearm is like telling the assistant director to check the camera angle or telling the assistant director to check sound or lighting.”

Torraco also would not confirm if Halls was the person who handed Baldwin the gun.

‘I didn’t pull the trigger’

Gun in hand, Baldwin said he and Hutchins began blocking out the scene. She was directing his every move, he said: “Everything is at her direction.”

“This was a marking rehearsal,” Baldwin said. “And [Hutchins] says to me, ‘Hold the gun lower. Go to your right. Okay, right there. All right, do that. Now show it a little bit lower.’ And she’s getting me to position the gun.”

“She’s guiding me through how she wants me to hold the gun for this angle,” he said. “I’m holding the gun where she told me to hold it, which ended up being aimed right below her armpit.”

What happened next remains a mystery. It’s the subject of intense public scrutiny and an investigation fronted by the Santa Fe County Sheriff’s Office.

To get the shot, Baldwin said he needed to cock the gun, but not fire it: “The trigger wasn’t pulled. I didn’t pull the trigger.”

“I cock the gun. I go, ‘Can you see that? Can you see that? Can you see that?’” Baldwin said. “And then I let go of the hammer of the gun, and the gun goes off. I let go of the hammer of the gun, the gun goes off.”

“So, you never pulled the trigger?” Stephanopoulos asked.

“No, no, no, no, no,” Baldwin said. “I would never point a gun at anyone and pull a trigger at them.”

Torraco, Halls’ attorney, corroborated Baldwin’s account on Thursday, saying Halls told her “from day one” that he was watching from three or four feet away and “the entire time Baldwin had his finger outside the trigger guard parallel to the barrel … that Alec did not pull that trigger.”

The aftermath: Chaos and confusion

After cocking and releasing the gun’s hammer, Baldwin recalled that, “first of all, everyone is horrified, they’re shocked, it’s loud.”

“[Hutchins] goes down. I thought to myself, ‘Did she faint?’” he said. “The notion that there was a live round in that gun did not dawn on me till probably 45 minutes to an hour later.”

Baldwin said accidental discharges of blanks or dummy rounds on film and television sets are common. In fact, crew members have since said that there had already been at least one accidental discharge on the “Rust” set just days before the fatal incident.

So when Baldwin’s gun discharged, he said it wasn’t immediately clear to him or anyone else watching the scene that something terrible had happened.

Baldwin said Halls telling him he was handling a “cold gun” added an additional layer of confusion because it meant the gun was supposed to be clear of live rounds.

In the chaos that followed, Baldwin said he wondered whether Hutchins had been hit by an errant projectile from a malfunctioning gun, like “wadding,” which packs gunpowder into the barrel, or perhaps even had a heart attack.

“No one could understand,” he said.

Hutchins had been shot in the chest with a live bullet. Souza, a longtime friend and collaborator of Baldwin’s, had been standing behind Hutchins when the discharge occurred and was hit with the same bullet.

Baldwin said he stood over Hutchins for 60 seconds, “kind of in shock,” he said, before being told to leave the area. Baldwin said he and other crew members had their eyes “glued” to the emergency helicopter that arrived some 30 minutes later.

He said he then went to the sheriff’s office. There, he said officers showed him a photo of a lead bullet that had been removed from Souza. That’s when officers told him Hutchins had died, he said.

“At the very end of my interview with the sheriff’s department … they said to me, ‘We regret to tell you that [Hutchins] didn’t make it,’” Baldwin said. “They told me right then and there.”

Crew complaints, claims of an unsafe set

Some crew members have described the fatal incident as a symptom of a production in disarray, leveling allegations in the press and in civil litigation of unsafe work conditions, long hours, insufficient housing accommodations and under-qualified hires.

Just hours before the shooting, several crew members walked off the set in protest.

Baldwin was wary of those complaints, framing the 12- or 13-hour workdays as common practice on film sets.

He said any allegations of an unsafe work environment were never brought to his attention nor, he said, did he perceive working conditions as unsafe.

Baldwin said that the day before some crew members quit, Lane Luper, a camera assistant, alerted him to issues with hotel rooms for the crew, but made no mention of safety issues. Baldwin said he was prepared to return a portion of his salary to support better accommodations. But the next day, without warning to him, according to Baldwin, the crew members did not show up.

“They decided to renegotiate the contract in the middle of filming, which is not a good idea, as far as I’m concerned,” Baldwin said.

Another target of public scrutiny – and the two civil lawsuits – is Hannah Gutierrez Reed, the film’s 24-year-old armorer and prop master. As armorer, Gutierrez Reed, the daughter of famed Hollywood armorer Thell Reed, was responsible for maintaining, handling, loading and unloading any weapons on set. When Baldwin arrived on set, he said Gutierrez Reed gave him a 90-minute demonstration on gun safety.

Gutierrez Reed had only worked as an armorer on one film prior to “Rust,” and was tasked with splitting her time between armorer and other prop-related tasks.

Baldwin, as a co-producer on the film, said he played no role in the decision to hire her. He said he served as a “purely creative producer … I don’t hire anybody in the crew.”

“Do you think she was up for the job?” Stephanopoulos asked.

“I assumed because she was there and she was hired she was up for the job,” Baldwin said. “I mean, I’m not a producer that hires the crew.”

David Bowles, an attorney for Gutierrez Reed, told “Good Morning America” last month that he believes somebody may have “intended to sabotage this set with a live round intentionally placed in a box of dummies.” Bowles added that Gutierrez-Reed had no idea where the live bullets came from.

Baldwin said it is hard for him to imagine that being the case, and said he believes it was “overwhelmingly likely that it was an accident.”

“That’s an enormous charge to make, that someone came and did something, for what purpose? To attack who? To discredit who? To harm me? The production?” he said. “What was their motive in doing that, if somebody did that?”

Responding to criticism and legal exposure

Baldwin has been named in two civil lawsuits, including one that accuses him of “playing Russian roulette” with the firearm by pointing it towards Hutchins.

In “Rust,” Baldwin argued, he followed the same protocol he exercised over the course of his 40-year career in film and television, and said he placed faith in the professionals he said were responsible for maintaining a safe set.

“In terms of the handling of the gun, that day I did exactly what I’ve done every day on that movie,” Baldwin said. “The actor’s responsibility is to do what the prop armorer tells them to do.”

“When that person who was charged with that job handed me the weapon, I trusted them” he continued. “And I never had a problem, ever.”

Halls told investigators in a sworn affidavit that Gutierrez-Reed opened the firearm used by Baldwin, but he could only remember seeing “three rounds” and that “he should have checked all of them, but didn’t, and couldn’t recall if Gutierrez-Reed spun the drum.” Halls also told investigators he didn’t know there were any live rounds in the firearm he gave to Baldwin, according to the affidavit.

Baldwin maintained that he would never misuse a gun on set. He reiterated that he was only following Hutchins’ direction and trusting Halls’ “cold gun” instruction.

“I would never point a gun at anyone and pull the trigger at them, never,” Baldwin said.

“There are some who say you’re never supposed to point a gun on anyone on a set no matter what,” Stephanopoulos said.

“Unless the person is the cinematographer who’s directing me at where to point the gun for her camera angle,” Baldwin said. “That’s exactly what happened.”

Criticism of Baldwin has come from fellow actors, some of whom shared their own protocol using weapons while filming. George Clooney said recently that, “Every single time I’m handed a gun on a set — every time they had me a gun — I look at it, I open it, I show it to the person I’m pointing it to. We show it to the crew.”

Baldwin took issue with Clooney’s thinly veiled jab, calling it “misplaced.”

“There were a lot of people who felt it necessary to contribute some comment to the situation, which really didn’t help the situation at all,” he said. “If your protocol is you checking the gun every time, well, good for you. Good for you.”

“My protocol was to trust the person that had the job,” he continued. “And it worked up until this point.”

“What is the actor’s responsibility?” Stephanopoulos pressed.

“That’s a tough question,” Baldwin said. “Because the actor’s responsibility going this day forward is very different than it was the day before that … I did the same thing that day that I did all the other days we were shooting.”

Santa Fe District Attorney Mary Carmack-Altwies told ABC News that criminal charges regarding the incident were “on the table.”

Baldwin downplayed his exposure to criminal charges.

“I’ve been told by people who are in the know, in terms of even inside the state, that it’s highly unlikely that I would be charged with anything criminally,” he said.

The personal toll

“Do you feel guilt?” Stephanopoulos asked.

“No. no,” Baldwin said. “I might have killed myself if I thought I was responsible, and I don’t say that lightly,”

The incident nonetheless left him scarred, he said, and continues to weigh on him.

“I have dreams about this constantly now,” Baldwin said. “I go through my day, and I make it through the day. Then I collapse at the end of the day. Emotionally, I collapse.”

Hutchins’ death has also made him question whether he wants to continue making films, he said, and said he “can’t imagine” ever doing a movie with guns in it again.

“I couldn’t give a s— about my career anymore,” he said.

“Is it over?” Stephanopoulos asked.

“Well, it could be,” Baldwin said.

After the shooting, Baldwin said he had the chance to meet Hutchins’ widower, Matthew, and her 9-year-old son.

“I didn’t know what to say,” Baldwin said. “[Matthew] hugged [me] and he goes, like, ‘I suppose you and I are going to go through this together,’ he said. And I thought, ‘Well, not as much as you are.’”

For Hutchins’ family’s sake and the sake of his own emotional well-being, Baldwin said he wants answers. He repeatedly alluded to his interest in the criminal investigation underway, saying he eagerly awaits its results.

Until then, he said, all he can do is reflect.

“You said you’re not a victim,” Stephanopoulos said. “But is this the worst thing that’s ever happened to you?

“Yes. Yeah, yeah, yeah,” Baldwin replied. “Because think back, and I think of what could I have done?”

“Alec Baldwin Unscripted,” produced by George Stephanopoulos Productions, airs in a one-hour primetime special event TONIGHT 8 p.m. ET/7 p.m. CT on ABC and streams on Hulu later that evening.

Next week, a two-hour “20/20” delves into the events ahead of the deadly shooting on the set of “Rust” and the pending investigations into what went wrong, featuring the Baldwin interview and new interviews. “20/20” airs Friday, Dec. 10 (9:01–11:00 p.m. EST), on ABC and streaming next day on Hulu.