UPDATE ON ARMAND:

I've been thinking and Armand, someone who suffers from ptsd, probably wouldn't want to hear his shotgun all the time, so it will now be a sort of secondary weapon, which would make this knife his main weapon

You'll switch weapons with right click.

And while he holds the shotgun he'll look a bit worried as, well, it's a last resort situation and hearing his shotgun may trigger his ptsd (it lowers your sanity and when it reaches 0 images of the things he saw will appear on screen, blocking your view)