Well I have the greatest almost Murphy came, brought his dad, grandfather, and all of his brothers only to move in story. This is a true story too.
At the old elephant barn we cleaned the waste in the morning and in the afternoon. We had to go through the bull's yard at the back of the barn to get to the truck to dump the waste. After bringing in Tonka so he could eat and drink and we clean his yard for the night, we went to the exterior gate to unlock it only to discover the lock was not in the slide arm rather it was sitting on a piece of steel where we put it every morning. On top of that, the slide arm holding the gate in place was in the open position. This meant Tonka could have gotten out of his yard at anytime during the day and escape into the zoo with the public.
If he had leaned on the gate he would have walked right through.
After that we double locked all external gates, pulled on each lock, said outloud "Locked" and had someone to go back and double check.