The name reflects the increased danger of the door falling open if it becomes unlatched while the car is moving.^] The potential risk is obvious: when driving at speed, the fast moving air around the car creates an area of low pressure, which acts as an outward force on the door, trying to open it. This usually doesn't matter as the latch or lock is keeping the door closed. On a conventional car, if the door becomes unlatched, the fast moving air around the car, which is going in the opposite direction to the car, will force the door closed. Whereas with suicide doors, the fast moving air, again moving opposite to the car, pushes the door open. This can be dangerous if the occupant is not seat-belted.

This problem is greatly increased when driving around a bend. Lateral g-force combined with the low-pressure air moving around the car will fling open an unlatched door, and the occupant will be thrown out if not wearing a seatbelt. In reality, this is very unlikely to happen because the locks and latches for suicide doors are specially built to withstand greater forces than most locks and latches. Most modern cars with rear suicide doors have front doors which overlap the rear doors so the latter can't open unless the front door is open. Another safety device is to use a lock that prevents the rear doors being opened unless the front doors are open, such as is used by Rolls-Royce.

Some erroneously believe that the name stems from the fact that if in an emergency, the user exits the vehicle whilst it is moving, the door will hit them upon exit.