I would have demanded a new room immediately. They can take as long as they like to fix the lock problem, because it would no longer be my room. If they tried to give me even the slightest pushback, I would escalate my level of displeasure until I got what I wanted. If they really annoyed me, I would have made a point to speak with the GM at some point and explain to them that they need to better train their staff in how to handle safety issues, and probably ask for some points for my trouble.