An odd thing happened on Tuesday night, nearly two hours into the 8:05 showing of Paul Thomas Anderson’s “The Master” at the AMC Loews Boston Common 19. As Freddie Quell, played by Joaquin Phoenix, was poised to throttle a man unfortunate enough to offer a frank opinion of the latest book written by the messiah-like cult leader Lancaster Dodd, and just as the squeamish among the crowd might have been tempted to avert their eyes from the impending violence, the screen went black. The audio, however, continued, leaving us sitting in near-perfect darkness, baffled but rapt, as we listened to grim sounds of punching, wrestling, and strangulation. Then, after perhaps a half a minute, the sound cut out, too.

Fin?

After a beat, someone near the front let out an exasperated, sneering harrumph. Others laughed nervously, or began murmuring to their companions. “Is that it?” “Wait, that was the end?” Soon the darkness was pierced by the faint glow of smartphones, as people turned to the Internet to sort out whether the movie was supposed to have such a sudden and shocking ending. Surely we’d have heard about it before now. Someone yelled out, “Is this the second time for anyone?,” forgoing the Web for a more immediate kind of crowdsourcing. Some Good Samaritan left the theatre to seek out an employee for an official explanation. Another person climbed to the top of the theatre to bang on the glass of the projection room. (That those boxes are likely unmanned these days suddenly became an eerie thing to consider.) The house lights had yet to come on, and we remained in a rare kind of total darkness.

Had we been assembled to see any of the other movies on offer that night, this sudden blackout would have been quickly chalked up to mechanical failure. Yet there was something uncanny and rather elegant about the timing of the events. The cut to black had seemed like a flashy directorial choice. Indeed, an earlier scene, in which Freddie assaulted another heretic, had taken place offscreen, behind a closed door. This was simply taking it to another level of abstraction: by transporting the scenes of violence from the screen to our minds, Anderson was echoing the kind of mental transportation at the center of the harrowing scenes of Processing (a psychological examination and initiation) between Lancaster Dodd and Freddie Quell. And, in some ways, the visual had become redundant: since we’d become so acquainted with the physical, animal power of Freddie, we could imagine his gaunt and sinewy body viced upon his next victim.

Even after the sound cut out and the picture failed to return, some of us remained credulous, or at least hopeful. This would not be the first time that a major-release movie had concluded on a sudden and polarizing note. What came to mind was the Coen brothers’ “No Country for Old Men,” which ends with the character played by Tommy Lee Jones recounting an enigmatic dream. The screen goes black just a moment after he says, “Then I woke up.” Audiences then were variously delighted, moved, or infuriated by that stroke of filmmaking. Of course, after that scene, the Coens ran the credits.

Here, we continued in the darkness, which, perhaps because of the intensity of the jaw-to-jaw performances in the film up to that point, had taken on a sinister and frightening atmosphere. It was all too clear that we were in an unfamiliar place, among strangers. Even then, even then, there remained a chance that we were involved in a slightly longer game, that sitting alone with our thoughts in the dark was a final requirement of the movie, a final forced confrontation of consciousness, or some such thing, and it was with this last ambiguity that a few of us likely held out hope. Perhaps we were inclined to go anywhere with Paul Thomas Anderson, who, even among non-cineastes has earned a reputation as a genius. Or, more generally, maybe no one wanted to prove himself a philistine or a rube. We never want to be the sucker who claps too early at the symphony. And no one wants to be unmasked as the guy who doesn’t get it.

The Samaritan returned with information: power outage, happened to several screens, they’re working on it, not sure when it will come back, you can get a refund downstairs. The joke, it was clear, was on the holdouts, those of us hoping for a kind of participatory magic that was not to be. Yet even though we missed the last act, it was as if we’d seen an alternate ending, and experienced a kind of alternative cinematic reality.