Devil in the details

So, in planning for his time in the makeshift "cell," Russell has to estimate how long the building will remain closed for the police investigation. He can only know when it is safe to leave by his contact with cohorts outside via cellphone. If it's as long as a week, he has to hope the investigators are not smart enough to bring in a longtime bank employee to help them look through the place. That person would obviously notice upon entering the storeroom that it had shrunk because the gang had to move all of the shelving units six feet closer to the door to make the "cell." Why would the crafty cops not do this, since they are scratching their heads as to what exactly took place in the crime scene?