People use water to put out fires because

Using water is one common method to extinguish a fire. Water extinguishes a fire by cooling, which removes heat because of water's ability to absorb massive amounts of heat as it converts to water vapor. Without heat, the fuel cannot keep the oxidizer from reducing the fuel in order to sustain the fire.

answer; the code in musculoskeletal system subsection is associated with deep tissue possibly to the bone;