Leaving impressive aesthetics for last, I think that this angle/FOV may be a better choice in this case. Why? Because it conveys the more visually important information in the scene. With the ceiling fisheye you gain a great deal of positional accuracy it's true. But at what cost? Remember a fish-eye, although it may be overhead, is not directly overhead everywhere, so there is still potential for obstruction of the corners. Not to mention almost total obstruction of under bunks/matresses.
The narrower angle FOV (corridor mode?), sacrifices some absolute positional information for critical body/facial details: Is the prisoner sick, is he sleeping, or concealing something? All these IMHO may be more important to CO's. As for blind spots, corner reflectors are commonly used already in such places and could be employed here in either scenario.
Also, considering what we can guess of the dimensions, a 360 is going to have a lot of wall detail, maybe a 180 would waste less pixels, and of course no one could argue against the fact that both views would give the most info.