I told what happened last Sunday when I tried to unlock the doors to the lab.
The top two keys are the original keys to the lab. The one on the left is for the main door of the Dynamics Lab. The one on the right is for my teams' office in the lab.
The one on the bottom is my main door key, broken. The notch at the point of failure was so big to begin with (as you can see from its original copy on the top), which caused the inevitable break at the most critical point. The other key does not have such a big notch at its critical point, hence its survival.
I think they should just change the lock and give us new keys for the main door, because I wasn't the first one to have had this happen to.