Start with giving them this letter.
Once given to them, if you are fired, smile at the money they are going to lose in a civil lawsuit to you.
Smart employers will pass this letter to their legal council, and when their council informs them of the multitude of laws they will be violating by forcing the "vaccine", they should quickly back down.
As well as "and that I will obey the orders of the President of the United States and the orders of the officers appointed over me, according to regulations and the Uniform Code of Military Justice." I can rightfully go against an order and say it's unjust or unconstitutional and that will lead to far far worse than me just getting out. Be required to get a killshot, which is absolutely coming, possibly before FDA approval, disobey orders and get a dishonorable or leave now? I'll pick leave now and avoid all that.
P.S. I'm not a reservist anymore so I have nothing to worry about :)
P.S already got my discharge. Enjoy your killshot!