All I can comment on (me being a newbie) to the electrical field, but almost an expert in the "medical" biz.....is that communication is of utmost importance.
The policy in re: Master keys and where they should be kept needs to be reviewed by dietary staff. (stretchy cords are wonderful)

Did this repair guy actually fix anything? Or just take it apart, scratch his head and put it back together?

I would send a note to bookkeeping re: the bill from this "service call".

It might not be a bad idea to also draw up a policy, if there isen't one already, on who should be notified prior to any repairs being started. (I once had to call the head of Maintanence to get the ok for the pest control guy).
May need to get some locks changed in that facility too! Can never be too careful.