I forget exactly how you do it. You switch to the mortar as you're going prone or something. This was in v0.2 or something so I'm sure it's fixed by now.
That's because you play a vampire in a house full of zombies who want to eat you. D (The name os a Sega Saturn game...1 letter XD) is a VERY good Survival Horror Game. VERY good, you should look it up sometime, maybe even get it on a ROM
Seriously, add some sex animations, since people cyber on their anyway, and it would add another layer of realism to the game that just about all others are missing nowadays (why can't I rape dead bodies in GTA like I can in real life?).