The lard does nothing, but, Malaiz has a healing scroll called Grace of a Dead Saint, which has great healing potential.
He's still too ill to cast it from his catastrophic casting failure from earlier, but someone else who (now) has a high Presence score (like Lord Margar) could try casting it instead...if Malaiz was willing to hand it over.
Prügl also has a special star sign, the Eastern Saint, which he can use to heal somebody (once) this day.
Back to the narrative:
Although spraying Lord Margar with burning acid, causing his armour to smoke and hiss (and some of his skin as well), and dissolving the beautiful rampant cock off the face of his shield, the sticky membrane does burn away from the fire of his torch, shrivelling up in a cloud of noxious smoke, exposing the remaining portion of the room beyond!
Within, Margar sees clusters of mushrooms scattered all about the rest of the room, sprouting from clumps of glowing moss, and a large dark hole in the floor, not far from where the membrane was stretched.
Lord Margar thinks he can hear a song coming from the bottom of this dark pit. There's something...familiar...about it...but he can't quite place it. It's more of a feeling. A memory of a feeling. Also, no-one else can hear it.
The room continues to curve around the outside of the central chamber. The corridor filled with burning bones leads into this space (see image below). There is a door at the southern end of the room.
MEANWHILE
Fechr turns the knob of the eastern door and opens it.
On the other side, he sees a room, lit by two torches on the wall. The room is bare, except for a corpse on the floor. The corpse's eyes are black, their skin purple. Silver coins are scattered all over the floor, scattered around the corpse. At least a hundred of them. A dagger is sticking out of the corpse's chest, and there is a pool of dried blood all about them. There's an open archway at the end of the room, facing south, but Fechr can't quite see through it at this angle.
This picture shows what has now been revealed by Lord Margar in the west, and Fechr in the east.
