Well considering I AM a particularly skilled martial artist (8 years and counting) i'd would probably just need to sneak up on someone from behind on choke them to death or if it's possible snap their neck, also just because they have automatic weapons doesn't mean they know how to use them. The gun may have it's safety enabled and no one would know or the recoil would make the guy twitch like schyzophrenic and if they go full auto in 10 seconds max they're out of bullets, i would try to sneak up on the weakest member and steal their gun, but i would also try to procure myself a knife which is much easier and silent to work with