The above attached video shows how to get into the under croft below where you obtain Khem Val, and a bonus treat for a boss in the same zone. I recommend doing this before obtaining the map and locking yourself out of the phase if you happen to die.
I am pulled between posting this as a guide or as a post in Exploration so I will post it here. Feel free to watch with the sound muted, and your own music if you don't like hearing a well done impersonation of Adam Savage's nerdy voice.
Anyways enjoy my small treat here, and I will be heading to sleep, and then probably come back to this and realise I posted it in the wrong section!