Eating, sleeping, playing well....and those cute little yawning stretches....also grooming themselves while out with you, or eating during playtime, tends to me they are quite comfortable with the Big Hand Monsters.
What does it look like he's getting away from? I know when Ziggy wants out for playtime, he can be violent, lol.....he's knocked the entire front panel off more than once. His snout should be registered as a lethal weapon.....
Some hams are also vocal, when happy....so, as long as he seems to be doing normal hammy things, he's probably quite content....with occasional splashes of true happiness
I do know when Ziggy tries to get out he wants to play...he's not trying to flee or escape anywheres.....when he has escaped, it seems he just thinks the room is a really really big cage to explore and run around in.