A bank teller can't know the gun isn't loaded. PTSD is a real bitch and could easily have ruined the tellers life permanently. If there were any customers in the bank they could have been a victim too. Families could have been destroyed.
Frankly 18 years sounds kinda cheap. If you have to rob a bank, at least tie a chain around the atm at 1 am -- more money and less hurt to all concerned.
However long it takes to make them not be worth it, though no minimum sentences. An normal of 30 years might do it, with some real incentives for reintegrating into society upon release as well as possible time of for good behavior (but not getting into fights is not enough to qualify for good behavior).
I agree, it is pretty strict but that is because it is a very serious crime due to the direct impact the gun has on people. Steal the ATM, break into the place in the night, sell cocaine, whatever, but don't fucking threaten peoples life.
Frankly 18 years sounds kinda cheap. If you have to rob a bank, at least tie a chain around the atm at 1 am -- more money and less hurt to all concerned.