The Envelope: Michael Keaton, Alejandro Iñárritu detail bumpy flights in ‘Birdman’

“What’s in this? Rum? Whiskey? I guess I’ll find out ...�

Why not? On a glorious December afternoon, Michael Keaton is up for anything, including downing a shot of a secret-recipe eggnog offered by a Santa Monica restaurant’s owner. (We’re guessing rum, by the way.) The main topic on the table is, of course, Keaton’s acclaimed turn in “Birdman� as Riggan Thomson, the Hollywood has-been trying to jump-start his career by staging — as writer, director and star — a Broadway adaptation of a Raymond Carver short story. We had questions about three of the film’s key scenes, and Keaton provided answers as best he could. Later, “Birdman� writer-director Alejandro G. Iñárritu helped fill in the missing blanks. (Yes: Spoilers ahead.)

After a rooftop epiphany, Riggan decides to go out with a bang on stage, spilling his blood, as New York Times theater critic Tabitha Dickinson would later put it, “both literally and metaphorically.� Keaton and Iñárritu agree it’s the film’s key scene, but for a while, they wondered if it would work at all.

Keaton: I wasn’t ready for this. I got caught off-guard because we had been shooting all day and it was late, and we were setting up and I’m going, “What are we talking about doing now?� It hit me. “Oh, my God. I thought that was tomorrow.�

Then I started to feel a little sense of panic. I wasn’t sure if Alejandro and I had ever talked about this scene. And as I’m hearing him talking about it, I suddenly realized, “I see what he’s seeing now, and I’m not necessarily sure I see it that way.� But then I started thinking, “I’m not sure how I ever saw it.� And it’s the white-hot part of the movie. I will admit that I started getting scared. And scared is not something I get. Then it was like Birdman was starting to talk to me, and I was really getting mad at myself for not being on top of it.

Iñárritu: That’s a very funny thing. We rehearsed in Los Angeles, and the first couple of days were very hard for Michael. He was struggling. He was rusty. He was thinking that we were just doing the blocking. But I wanted the emotion too. Then we came to do that last scene, and he did it with a pace and rhythm that, for the first time, I saw the character there. I turned to Chivo [cinematographer Emmanuel Lubezki] and said, “Exactly!� We both saw it. From that moment, Michael started understanding that this was not a high comedy. It was seriously funny. But not funny. That was the first time he did it right. And now, when it came time to film it, he forgot the whole thing.

Keaton: I just could not get it. It’s usually in here somewhere around me, and I’d get it when I’m in the scene. But I did it again, did it again, did it again, and now I was getting frustrated. I went backstage and told Alejandro, “It’s not there man.� And he knew it.

Iñárritu: When we did the first pass, there was no emotion. Second take the same. Third take and he was more lost. And if that scene doesn’t work, it would be a disaster. It was the dramatic, emotional pinnacle for the character. Also, I was paying 1,000 extras sitting in the theater — and it was the last day we had the theater. So it was now or never. And I bring Michael to this little room backstage and I tell him, “You remember the rehearsal? I don’t know what image, emotion or memory you connected with that day, but return to that.� And he was really nervous. He said, “Give me three minutes by myself.�

Keaton: I was out of things to think about, out of things to feel. I was so empty that I just reached this really interesting state that’s never happened to me before. I just did this thing that got me out there. And when I was on stage, everything stopped for a minute and I found it. Alejandro loved it. He’s a hugger. He couldn’t stop hugging me.

Iñárritu: Later, we had a drink, and I asked, “What happened in those three minutes?� And he told me he just opened his shirt and lay down with his stomach on the floor and asked Mother Earth, “What is truth? What is the truth now? Help me.� Which I thought was a beautiful way to find an answer to something that is impossible to know. Truth is everything. And he found his truth through that process, which I found poetic and primitive and beautiful.

An earlier scene, which finds Riggan forced to march through Times Square in his underwear after being locked out of the theater, also caught Keaton off-guard, if only because he had subconciously dismissed it from his mind after first reading the script.

Keaton: Actors will say yes to anything. Then the day comes and you think, “What happened between the time I read it and the time when I’m dropping my pants?�

Iñárritu: We got four takes. I knew the situation would deteriorate once people [in the crowd] discovered what we were doing. Everyone would be looking in the camera, saying hi to their moms. The one idea I had was to hire this band to play drums to distract the crowd. So we cued them to start playing, and that’s when Michael begins his run.

Keaton: My favorite part of that sequence is the robe getting stuck in the door. I’m not sure I nailed it. But I liked the idea of this guy thinking, “If I don’t stand upright. If I walk like this ...� (Keaton pops up to demonstrate Riggan’s would-be furtive, hunched-down speed-run.) “... then maybe no one will see me.�

People ask if that scene was hard. “Hard� is a non-issue. You’re just in it. There were little flashes, yeah, “I’m in my underwear.� But that was a good feeling to have. The sweet spots of that scene for me were the robe, the trying to get away, signing the autograph and the entrance to the theater. In one take, I switched the fake gun from one hand to the other. That was so much fun.

Iñárritu: I took the dailies home, and I remember I couldn’t stop laughing for hours. All the little details he brought ... it was like a silent film Buster Keaton performance.

The film’s ending has generated much debate. After shooting himself on stage, Riggan lands in the hospital, where he’s visited by his ex-wife, daughter and manager. He has a new nose — and an apparent new lease on life. But that doesn’t stop him from climbing out on the windowsill. When his daughter returns to the hospital room, she finds it empty. She goes to the window and looks down. Nothing. She then looks to the sky and a smile washes over her face.

Keaton: That ending wasn’t in the original script. Alejandro wrote it while we were making the movie. And when he read it to me, it made perfect sense. I know what it means for me now, but who’s to say that won’t change in a month? Or five years. Its beauty lies in its ambiguity. You don’t know. I don’t know.

Iñárritu: There are as many ways to interpret the ending as there are seats in that theater. And I’ve probably heard every one of them. [Laughs.]