As a teenager she would 'sneak' out (of her house/apartment) at night to visit her boyfriend.
I'm going to 'sneak' a smoke. [=I'm going to smoke a cigarette while nobody is watching]
She took a 'sneak peek' [=a secret look] at the birthday presents hidden in the closet.
(..) Loki is a prisoner. Then why do I feel like he's the only person on this boat that wants to be here? There's not many people who can sneak up on me. But you figured I'd come. After. After whatever tortures Fury can concoct, you would appear (..)2012 The Avengers