Newtonian dampener.

grabcad

This is a hydraulic dampener. It can be built inside the ceiling above the door. It can be used with almost every doortipes, and becouse its easy to resize, it can be used with every size, and weight door. In the unlikely event of emergency, an ususal hydraulic dampener would make the movement of the crew, and passengers hard, and slow. But this one is equipped with a "failproof" system, which will disable the dampening if necessary. The working method: The system has a built in electromagnet, and a static magnet. If the electromagnet stops working, the static magnet(and the gravity) will pull down a metal bar, which opens to valves, so the liquid inside the device can flow out, which will disable the newtonian dampening effect, so it will be easy to open the door. Becouse the electromagnet holds up the metal bar, it cant fail even if the cable, that connects it to the main system of the ship burns, or receives another kind of damage.