Some TMNT stuff really isn't for little kids.
Fun with Guns is a 14-page comic originally published as a backup comic in November 1987 in Raphael: Teenage Mutant Ninja Turtle (2nd printing) by Mirage Studios. It was later reprinted in Shell Shock.
Raphael and Casey are caught in the middle of a gunfight, in which Casey's newly painted mural is destroyed. The wounded man, Buck Dooney, tells them who shot him and that Casey and Raphael can find him in a nearby pool hall, Vern's Pool Hall Royal!. After calling an ambulance for Dooney, they go to the pool hall and find a gun storage room in the back, but are discovered while breaking in. After a short fight Raphael is captured by the criminals. Casey is separated from him, but soon returns wearing a big bulletproof suit. Unfortunately, even though the suit saves his life, it's too cumbersome to move in, so he ends up falling through the floor, triggering a catastrophic structural collapse of the pool hall's floor that drags the rest of the people in the room with him. The police find the unconscious criminals and arrest them while Casey and Raphael slip away.