Are you following the directions given to you on the computer? Because when you wander outside of the directions (which indicate safe rooms) there's a chance it could be an unstable room.
Incidentally, there is a tell, but it's very subtle.
Viewing post in Immediate death with no warning is frustrating
No, I wasn't following the directions. Entirely my own fault, I didn't even realize the arrow glyphs were the directions to get through the maze. I'm going to blame attempting the game before I had my morning coffee.
I tried it properly now, and succeeded in getting all three things. Thanks for helping, I was clearly being dense.