The dangerous bank robbery

The Murphy boys sat outside the bank and Pat outlined the plan for the stick-up. 'Now, youse three put the masks on and leap into the bank. I'll be staying in the car. Then youse'll pull out the pistols from your trousers' pockets and tell everyone to lie on the floor and be quiet. Meantime, I'll be in the car doing the dangerous part. When everyone is lying on the floor you'll grab all the large notes and shake them into a sack. Meantime, I'll be in the car doing the dangerous bit.'

'Hang on, hang on,' said brother Mickey. 'We're doing all the sticking up and shouting. You're in the car, but I don't understand why it's the dangerous bit.'

'Well, you see,' said Pat, 'it's dangerous 'cos the car's not taxed!'