Kanako Oba contacts a mysterious site for part-time work. Because of this, her life is soon in jeopardy. She is then forced to work at the restaurant Diner as a waitress or she will be killed. Bombero (Tatsuya Fujiwara) is the owner and chef at Diner. The restaurant is membership only and their customers are all contract killers. Based on a novel by Yumeaki Hirayama. (Asian Wiki)
Someone unexpectedly bites down on a coin in their food. There's a crunching sound and you might think their teeth are damaged, but they seem uninjured.
Some henchmen get their clothes set on fire, it's not very graphic and we don't know if they die. Other bad guys apparently die in fiery explosions but nothing much is shown.
A dog clamps its jaws around a guy's skull and slowly increases the pressure, but the head doesn't really get "squashed". The guy's head bleeds but the wounds seem pretty minor because he survives and walks away.
There's a rather disturbing scene where Kanako is groped by several drunk diner customers. She protests and tries to struggle out of their grasp but they hold her down. The drunk guys ask the chef if they can "buy" her, but it doesn't go any further than that. The customers are over-the-top ridiculous personalities and the scene is played for laughs, which may make it worse for some viewers.