What we (need to) know so far

Here is what we know so far, these will be critical in the moments to come: 

1. Murk is hurt, perhaps critically, he will use his alchemy to cure or something of the sort. 
2. There is a corridor underneath, it is 10' wide and heads north, for now. 
3. No doubt the map points to greater things underneath, something out there, something good, something big, and hell who knows something evil.
4.  At this time I am not sure if he has his armor, maybe this is the mission where he finds it no? 
5. What or who constructed underneath the crypt?
6. Is Murkstav alone on this mission?