Except that the Fallen are excellent at stealth and guerrilla warfare. They'd be able to figure out a path through the Gorgon's maze without much trouble, especially with invisivandals to go ahead and scout the patrol routes. I think they'd have the most trouble getting through the gatekeepers, honestly. It's not something that rewards being able to pick things off and take things slow. You gotta rock through it like a damn hurricane, something I don't see the Fallen doing.