Military question regarding severance pay?

So im going to make this as quick as possible... so if i were to get out of the army with a service related disability and get severance pay at 23,000 that severance pay is taxed. Even though I receive it from injuries which by law it is NOT supposed to be taxed but they greedily tax it because technically its doesnt go under none taxable until after a va rates the injury which then makes it harder for anyone to get it back... FUNNY how they get off on the uninformed .

So lets say they tax it at 28% and tell me that i need a va rating and blah blah before it falls under non taxable. Now since i am way in head of the herd with this i have not even got a severance pay rating so is there a way that i could get a va rating before even getting out of the army and receiving my future severance just so that the money that i will get can fall into a non taxable state before they even give it to me

so that i would not have to go through the pain of getting all the paper work and jumping hurdles to get MY money back if they tax it beforehand?