True Story: About 30 years ago, i was in a conference room with 20 others in a modern office type building. The meeting ran late on a Friday night and we could hear the traffic in the outside corrider clear out as we were trying to complete the meeting. No windows to this conference room, just the one door.
We go to open the door and it would not open or budge. We banged on the door several times but we were apparently alone in the 4 story building on a Friday night. And work didn't resume till Monday morning. And this was no lightweight door, hinges or lock - commercial/industrial quality.
Luckily i carried the Swiss Army tinker knife like the one below in my pants pocket. I pulled it out and gave it to one of the stronger members of our group, who used it to pry the hinge pins out and then we were able to remove the door from the metal jamb. I got some good natured ribbing over the wimpy nature of the knife, but many seemed grateful that we got out of the predicament in less than 10 minutes. There was no phone in the room and at the time, noone carried cell phones.
I suppose if i hadn't had the knife, we probably would have waited for an hour or two for some security guard to find us. Failing that, we probably would have used chairs to break through the sheet rock wall.