It seems unlikely to me that Hamas would have deployed Manhattan-Project-level counterintelligence work so that they could hide some guns in an MRI machine’s room, instead of maybe just stashing them in a broom closet down the hall.

It’s possible, sure. But this is my opinion on its likelihood and that sounds reasonably grounded to me.

An alternative explanation that seems more likely to me is that the IDF really wanted to be able to publish some photos that indicated that Hamas was using hospitals as armories, and so they propped some guns up next to a highly recognizable piece of medical equipment found only in hospitals so they could get those photos. Maybe the guns were taken from the broom closet down the hall, maybe they weren’t, I don’t have any basis for an opinion on that part. The rest seems most plausible to me in the meantime.