You were in the bank, not to withdraw money, but to rob it. Your two companions were quickly emptying the vault while you were keeping everything under control in the hall, keeping everyone on the floor, too bad the attendant pressed an emergency button under the counter, when suddenly the police siren could be heard outside.
To get away unscathed you take a hostage, in fact you just grab the nearest random one and drag him out, pointing the gun at his head. Back at the shed you and your partners in crime were planning to stop at to get organized, you keep your hostage tied to a chair with ropes and silver tape just in case, and he doesn't look happy at all.
"Bâtard! Let me go now!"
Being kidnapped wasn't in his plans, and taking a hostage wasn't in your plans.