Peter grins what is perhaps the most mischievous grin that he has ever grinned, which is probably a cause for concern. It's fiiiiine, don't worry about it.

"Oh, don't worry. The stairs won't be a problem at all."

Gotta be quick and efficient, right? So, what he does is more or less sling Kabal over his shoulders, so he can fireman carry his shroomed-out ass down the stairs. He's got this and it's perfectly safe it's fiiiine. But if Kabal pukes on his shoes, he's gonna be annoyed.