[NYCSkin]

A superficial knife wound to the chest would likely not penetrate the chest cavity. If a knife wound did penetrate the chest cavity then Banks is in danger of having a pneumothorax (the lay term is collapsed lung) which is commonly treated by inserting a chest tube to prevent a more serious complication called a tension pneumothorax. Seen plenty of those in my DC General days...

He's also a little/thin guy so he would likely be fairly susceptible to blunt chest trauma.