Okay, so:
The robbers started the robbery as planned. In the process, they fired a shot with their gun as a threat. The shot hit a car outside the bank, causing the driver to panic and hit another car, causing an accident. The man in the other car was a bank teller, working at the bank that was robbed at the moment, who wanted to get to work but was unfortunately killed in the accident. Because of the accident, the robbers couldn't get away in their escape vehicle and got caught by the police who had been called by the people inside the bank.
Anything else still missing?