Had a bit of treble installing when my cousin and I discovered my hot water hadn't been turned all the way off (when I couldn't turn the knob anymore I thought that meant it was shut off but it really meant there was a problem with the knob and the hot water was very much NOT turned off). So when my cousin went to detach the hose, hot water poured out of the line in an impressive, unstoppable burst. And with the knob still stuck we had no way to stop it. Had to call my building maintenance guy and he ended up doing the rest of the install, probably to prevent us from creating any more plumbing emergencies for him.
It could have been a real mess except my bathroom has a drain in the middle of the floor -- I call it my murder bathroom -- so instead of flooding my neighbor's apartments with 6" of water and becoming my building pariah, I (mostly harmlessly) discovered I am NOT a plumber, my cousin and I got a story we can laugh about, and I got my bidet install finished by my building maintenance guy (albeit with some serious eye rolling as well as professional-grade side eye). I made a batch of homemade cinnamon rolls for my apartment building staff to thank them for the trouble and for not making me feel like an idiot.