I was on my shift in a student accommodation and had to disable a fire alarm. The lock was jammed and the alarm sound was going off in the building with all other students outside. I got impatient and ripped the lock to disable the fire alarm, also fucking up the plastic key in the process.

I like this job and this is stressing me the fuck out. How should I approach seeing my employer tomorrow? Should I say it's all my fault or should I say someone had meddled with it before(I think someone had, but it could look like im just throwing the blame to someone else)? Should I just say that if it's a big problem they should take it out of my pay to fix it?

Help me m8ts, its an easy job and I need the money since I'm a student myself. I've had another recent fuckup, which wasnt as big, but messed with my track record. I'm a bit assbergy as well, which doesn't help.