> Additionally isn't there more analysis ? What are some scenarios ? I mean crashing after a failed launch attempt on the moon would perhaps be less disastrous than on earth, but can you realistically hope to survive a fall of several kilometers ?

I am not an expert, but I guess that the letter was mostly intened to cover cases where the https://en.wikipedia.org/wiki/Ascent_Propulsion_System failed to ignite at all, or perhaps sputtered early enough that the astronauts had a relatively soft landing after failing to make orbit.