Sorry to hear about your ghoul tinymouse, we will make Boris pay! I'm trying a GhFE right now too. I'm worshipping Kiku and planning on heavily abusing the "invoke Torment by praying over a corpse" ability once I get it.
EDIT: He died, to an overwhelming surplus of threats. I came down a level and found some electric eels I didn't want to mess with one way, so I went the other. There was a vault full of orcs that way surrounded by water (ended up leading to the orcish mines. I was dealing with the orcs slowly, drawing them out of the vault, and eventually I went inside to mop up the stragglers. I found a few orcs and drew them back to the entrance so I could fight one of them at a time. As I'm fighting the last one, suddenly there is a big drop in my health bar. A shark has popped out of the water. I back out, away from the shark and the orc, and another shark pops out and they both bight me down to red zone hp. I back away one more time and now have single digit hp, but I'm away from the sharks. I quaff a potion of healing and kill the orc. Suddenly a yak appears from the direction I had come from. I have to walk around the yak, luckily he misses twice, then I sticky flame and let that kill him as I back up more. But oh no, the eels from back there have woken up! I back away and they don't notice me, but one "just happens" to decide to follow me all the way back near the orc area, where an orc has popped out and blocks my escape. My subsequent fight with the orc alerts the eel, whom I attempt to escape from by using an escape hatch down (a dangerous plan, as I only had 20ish hp), but the plan fails as the eel moves into position and launches a shot of lightning, hitting me twice and killing me. It was just a never-ending escalation of threats.