My building has an accesibility elevator and doors are locked using triangle key, problem is that fails quite often and builder only provided one emergency key. Also they are hard to find and the only availables are bulky so decided to make a lighter version. It has a hole to carry it on keyring or pass a 4mm screw to help making force.

Keep in mind that due to small tolerances and the way 3d printing works, it wont be as strong as a metallic one, depending on the spring used on other elevators may be reusable or just single use, for emergency. I'm considering adding a cyanocrilate "paint" to increase resistance, if you have ideas about this, will include suggestion here ^_^