I have forced open a door once. We were in voice contact with the pt. She fell and had been lying on the floor for several hours. She was telling us that a door was unlocked, but it wasn't. We tried several windows and even tried to stick a skinny guy in through the dog door.
After, what I determined to be too much time fiddling around with it, and a pt whose LOC seemed to be diminishing with time, I grabbed the halligan tool and popped the door lock. Pt was diagnosed with multiple fx to her lumbar and sacral spine and was slightly hypothermic. I had permission to pop the door lock from the pt.
Without pt consent or visual confirmation through a window that a pt is in danger, we have to call a LEO to break the door. We had a frequent flier who was a major pain. One of my favorite parts of a call with her was standing outside with her cussing at us, spitting mad, while we waited for the sheriff to arrive. Once she even scooted over to the door on her butt, unlocked the door then scooted back over to where she was 'hurt and unable to get up'