PreARM in a momentary switch (trainer)???

[RipperGOT]

Hi!
I need more switch, moreeee!
To be able to use the switch that I currently use to prearm in another function. Can I put prearm in the momentary switch ???
Hold down trainer (prearm), arm, and release the switch. (And it's much safer) If you don't hold it down, you can't ARM

Is there a problem or does it affect something if prearm is not pressed during the flight?
In tests without propellers, switch off prearm and nothing bad happens. But maybe in flight, it's a problem.

Thanks friends!