Yeah, it worked great for his wife, didn't it? Oh wait.

Finn relaxes when the airlock hisses but doesn't exactly start sucking him out or anything. Looks like he docked close enough. Attempts to cut into the Marsiva, however, are met with minimal success: the ceramic hull of the ship is built to withstand great force and heat, and though Vader can get past the first few layers with effort, under that is a layer of seemingly impenetrable cables, gears, levers, and other mechanical devices made of a very resilient material.