Fires volatile grenades that explode on direct contact with enemies and deal AOE damage within 4m. Dormant grenades eventually explode and can also be shot to detonate early.
Unlock Information
Behind a bookshelf there is a hole that leads you to a platform area. There should be a pipe clogged by an enemy, shoot it and let 90 minutes pass (you can do other thing in other areas). After that the water level will be raised and use the planks to get to the weapon.