There is a plate that they screw into.When you screwed them out,the plate dropped down and the screws won't reach it.Just did an EBD playfield swap,that is how I know.

It will take some skill but you can do it without dropping the whole assembly.Take one screw out of the switch.Use the one screw to fish around through the plastic hole until you line it up with one of the plate holes.Screw it in enough to pull the plate up to the bottom of the plastic.While holding this with one hand,use your other hand to bring over your switch assembly.The switch assembly will be slightly rotated to the side enough that you can get the switch screw started into the plate.Now with the switch screw holding the plate,you can remove the first screw and swing the switch assembly in line.You get the rest.