How much mobility should the victim have? Complete immobility, some freedom to squirm and struggle, enough to attempt an escape?

I remember once seeing a comic of a girl trapped in a room with an enclosed bomb. The door was locked tight, but she wasn't restrained in any way. Was free to run back and forth in panic, pound on the door, flail in panic, collapse in despair, etc, all the way up until her death. Wish I could see it again, though I'm pretty sure I'm making a lot of it up.