The rocket trident is capable of sustained flight for five miles on a single charge. Eddie doesn't use it that way -- never has. Once he gets to a rooftop with a clear path to another, he lands there and runs. His path is determined by the tracker, and he only uses the rockets in short bursts in order to carry himself over the large gaps between rooftops that he wouldn't be able to jump on his own.

So he's in a good position to scale up to the roof of the theater, slipping in at a spot where the aged roof broke, pieces falling into the attic storage space. He presses up against the wall when he has to descend a set of stairs, knowing it's usually the middle of the steps that get the most wear and are more prone to make noise. And he's straining to listen for any voices, through the communicator or not.

...the mannequins are fucking creepy, though. That's his first thought when he catches sight of them around the main stage.