I won't spoil it, but there IS a reason Doss won't carry a firearm. He's bullied and harassed by everyone to quit as they don't feel Doss on the battlefield will save their lives and that he could put the entire platoon in jeopardy.
What transpires through a series of events is Doss ends up changing how we see non-combat individuals forever.
I am SO glad I watched this movie, and you will be too. Originally I didn't want to give it a chance, then Andrew Garfield got nominated for an Oscar. I kept thinking about it. I finally got the chance to watch, and it blew me away. So many untold stories to tell. This was a truly inspiring one; Andrew shoulda won that Oscar. WOW! Check it out...