This is like going up to door 22 and trying different passwords on the keypad until the right one is found. Various countermeasures are available, such as having the keypad lock people out on multiple failed attempts, or switching to a key-card entry (the employee must present a key-card rather than enter password). Such countermeasures are essential for security, but don’t solve the problem of criminals rattling the handles every few seconds. To help with that, one possibility is simply moving the employee entrance to a different door (a different port). This way door 22 doesn’t even have a handle to try – as long as the crims don’t know where the employee entrance was moved to, they would simply encounter a bricked-over entryway where door 22 used to be.