Cash is lost all the time in banks...a lot.All cash lost within the bank or in transit is insured.So no need to panic.You should only be worried if there is pilferage on customer deposits because the bank would then have liquidity issues if you were to withdraw.All the same, I think strong risk, audit & compliance policies need to be put in place.
You also notice most banks don't prosecute inside theft cases coz it injures their reputation, also considering they got the stolen money back via insurance.Another reason is because the Banking Fraud Unit will come in,harass all the wrong people and leave the culprit.
Formally employed people often live their employers' dream & forget about their own.