1. It is as we suspected. This "Geishu" is so incredibly accurate with his tommy gun that every single bullet went into his victim's neck. Not a single one hit the surrounding walls, or any other area of his body. Surely this was an intentional portrayal on the part of Davey.
2. The students depicted here give us a bit of a cultural insight to Davey-Kins's depiction of Japan in this era - it appears that a mullet is a rite of passage which, as students, they have yet to undergo.