We’ve all done it a million times – but ER doctors say we need to STOP trying to catch the elevator after the doors start closing. The reason? Because if you wave your arm or leg above or below the sensor, or the sensor isn’t working, the doors will close anyway. And elevators actually have four doors. Two on the elevator itself, and two on the floor you’re on. Meaning, it’ll catch your arm or leg twice, making it twice as tricky to get it out. And once the elevator starts to move, it can crush, twist, or even amputate whatever limb is stuck in the doors. Bottom line: You’re better off waiting for the next elevator, or swinging something less vital across the sensor, like your handbag or shopping bag.