So, Ranged enemies. Best ways to deal with them?

Recently there have been situations where I find myself getting gunned down by 5 or so Gunners or Shotgunners that spawn out of thin air and I'd appreciate some tips on how to deal with those.

If I'm being honest my main gripe with them is how to deal with them when there's multiple of them in an open area and my teammates ignore clearing them.

(I play Auric and Havoc 20+, yes I know it might be a bit late for that question but idk. Other than this minor issue everything else is smooth or butter)