Haha yeah, Drimmle is basicaly asking Marc to kill him. He's asking her because she's seen into his thoughts.
Marc is a relatively gentle person and has apprehensions about it. So she's thinking she'll put him to sleep in a loop of his best memories, so he can wake up from it if he wants to (i.e decides not to off himself). Alternatively, he could remain alseep at which point he'll die of dehydration in a few days.
Marcs hope is that he'll come to his senses with some sleep (i.e Drimmle spends all this exp reducing his Insanity points) and wakes up.