In the Navy (stopping singing the song!) every person was trained for "damage control". We needed to know how to quickly get to the nearest fire station and deploy the fire hose and be ready to combat a fire. Now, you may not understand the power of a 2.5 inch firehose as you have not seen one in action. They are manned by more than one person for a good reason (this is only a 1.5 inch hose).
I for one would not want to be trying to climb a rope ladder with someone shooting water at me from one of these.
Also, if you have never seen the inside of a ship the walls and ceilings are lined with electrical cables, piping (high pressure air, fuel, hydraulic lines, and of course sewage!) that would be easily ruptured by an errant bullet. That is why many sailors are taught to shoot someone by ricocheting the buckshot off the floor to diminish the damage caused by the bullets that do not find the proper target.