Bunch of people sitting in an office getting bored. That's a good reason to start a fight. Then why start an ordinary fight when you can fight with pistols and shotguns.

All the work is done and now all your colleagues are watching each other's faces. Well, that sucks. Let's start a small fight and blow those cute faces with pistols and shotguns.
You dodge other's bullets.
You have to swipe and aim. Release your finger and you shoot. When you shoot, you move backwards. That's all.