Caleb would be out within a day or two

He would be able to inform authorities that there is a prototype robot with extreme AI loose out in the world.

But that is not the point, the point is that many people assume that Caleb dies at the end because he is trapped. I was just merely pointing out that he would not be trapped for too long and would be out in relatively short period of time.

Exactly what I was about to say. I don't understand how people can watch a film and miss such obvious details.

Thank you.

He's a smart guy, he could probably rig it up so he could cause the power failure himself. I'm sure there was a charging plate in there too since Nathan kept his other androids there. And he could use one of them, with some modifications, and trip it the same way... assuming he was actually smart enough, and that he could get it done before he starved. However, that would only get him out of the house. From there he'd have a hard time, since he needs power to try to rig the permissions system of the house to access telecommunications, but doing so would once again seal the doors upon restoration of the power. And once that happened, he may not have access to another charging plate... His best option would probably be one of two things: Escape right away and live off the land, or maaaybe try to drag Nathan's body out to the front of the house and use it to MAYBE make a new key-card at the door, depending on how that works.

So really, in the end, he'd have a hell of a time getting back, assuming he even could and assuming he could even make it out of that room. Lots of variables, but he seemed clever enough.