"Favour!" Rincewind squeaks. "That's not what I'd call it! Have you seen all the scars on my back?! I can only hope my enemies treat me better than my friends!" He's started shouting and waving his arms. "All I want is a nice, safe, boring life! I don't think that's so much to ask! OW!!!" He hollers, more from reflex than pain. "SEE WHAT I MEAN?!"
"I don't mean to," Rincewind says miserably. "Truly I don't." He sinks down, resigned. He pauses, but only for an instant. Crawling (or running) away is something that best done quickly and devil take the hindmost. As usual. He rises to his hands and knees and begins scuttling away. He manages a surprising turn of speed.
Of course, and it is a unstated given that Rincewind is the chosen of The Lady. But he has no idea and must never know, because the instant he thinks he's invulnerable, he won't be. She is the bitch goddess after all.
I wouldn't dream of standing in the way of Xel's fun. Carry on regardless. :D