Locked In is the latest in a long line of B-movie psychological thrillers that seem to place much more importance on the kind of twisty structures they can pull off, rather than the actual content of their stories. Formal experimentation is just as valuable of course, but when a story like this—that relies on the shock of how these various character relationships turn against each other—can't give us characters with any sort of real interiority, the flashback-heavy narrative just begins to seem like unnecessary noise. Trying to keep up with basic emotional beats shouldn't be this complex, and after a while you begin to realize that these people are simply doing things outside any proper context, suspended in a world with no weight or specificity.

The actors do a fairly decent job given the absolute dearth of good material they've been given, with Alex Hassell as a somewhat compelling doctor character who remains shady no matter how the narrative tries to portray him. But this is all too little too late, as the film only ever gives the actors things to react to, and very little space to develop who these people are and what drives them. This is once again the temptation for psychological thrillers, to think that having everybody be unreliable makes up for weak characterization, but that really shouldn't be the case.