[RPG] Mechadendrites in dark heresy: sourcebooks and guidelines

There will be two attacks. On page 190 of the main rulebook, under the Full Auto Burst heading, it says that if you have two pistols in your hands you may fire them both. Page 197 discusses two-weapon fighting, and while it doesn't explicitly say that you make two attacks, note that two-weapon fighting with a melee weapon and a pistol does call for resolving each attack separately. Also, there's no stated bonus for using two weapons other than the potential for two attacks, which strongly indicates that you get to make two attacks -- otherwise, you'd never do it.

As a sidenote, also per page 197, you may only lay down one area of suppressive fire even with two full automatic weapons.

If you are the guy with the temptation to go for the easy joke, this may be extraordinarily difficult, since as GM you really have the opportunity to set the tone.

Maybe you need operant conditioning. Every time you go for the easy joke, throw a token in a jar that the players can use as a bonus of some kind. Make them the arbiters, so they are both watching for you to slip up and tacitly monitoring their own behavior.

Maybe you need a way to express this stuff directly. Sometimes playing an inherently over-the-top setting absolutely straight is just not viable, and injecting a little appropriate recognition of the absurdity is both a relief and helps maintain focus. Maybe have a comic relief NPC, a guy who recognizes the ridiculousness, a sort of court jester, and use that guy as your mouthpiece for that stuff.