“if the path is too narrow for the diver with oxygen tanks strapped on to get through”
Wonder if a long hose would be helpful, like deep sea divers used to use. The hose or an accompanying cable could also be used to pull the divers through. An accompanying electrical wire would allow communication with people on the outside — can you talk inside a diver’s mask?
It’s called a hookah rig. But there are limitations as to how muche air volume you can move down the hose. Plus dealing with another iteman that risks entanglement... in the dark, in dirty water, with limited ability for another diver to assist. This rescue is fraught with risk.