Would be extremely interesting to build an "Exploration" node of sorts. Solve a sort of Semantic SLAM problem as you go.

So if you can give it an instruction to "Find the elevator on this floor", could it walk around and build a map as it goes so it starts doing what a human would do to find the elevator.

As of now, the way these navigation models are setup, it assumes the instruction writer was intimately aware of useful visual navigational landmarks to give, which is not realistic for most use cases.