Why is it that every hospital building (the very tall kind) has a floor in the upper floors that protrudes out?

It is the surgical floor. Tertiary hospitals will be divided into departments, hospitalized patients are more, generally large ward building, medical measures are higher, will be set up surgical floor. There are various operating rooms on the surgical floor, which need to be clean and dirty partition. Medical staff and patients will be sterilized before entering and after coming out. In the operating room generated medical waste, need to discharge, not along the original path back, will protrude a piece, forming a corridor, there will be a small door next to it, there will be a special person to carry the discharge of the basement, to prevent cross-infection.