My opinion on locked bedroom doors-it is a safety issue. If there were an emergency that required an evacuation, getting that door open would be a problem. Can it be easily opened from the outside?
I have autistic relatives and a background in special ed, so I understand that suddenly making the door not lock could be a HUGE issue.
If it can't be opened from the outsidex can you replace the door with a really flimsy hollow core door and keep a crowbar nearby?
Our interior doors lock, but there is a hole in the center of every knob where a pin can be inserted to override the locking mechanism.
Glad to hear the gerbils are ok. They are one of my favorite rodents.