I know that because of the height of the Starship Human Landing System it has an elevator on the outside to lower astronauts down to the lunar surface and back up again, but has the risk of the elevator not working once the astronauts are on the surface been considered? In that event having emergency step rungs on the side of the craft might be a good idea, and since the craft operates in the lunar environment which doesn't have an atmosphere having rung protrusions on the outside of the lander wouldn't be an aerodynamic problem. Incidentally as the HLS is about 50 metres high the airlock would probably be about 40 metres above the lunar surface, so even in lunar gravity a fall from that height needs to be avoided, therefore if step rungs are needed to be used probably best for the astronauts to have a tether that they can clip onto each rung in turn while ascending.