Like Roger said, it's normal and he's just exploring his environment (translation - looking for a way to escape). My son's ig is in a large cage with 1/4" mesh all around and on the top. She climbs along the wire mesh all the time, and often walks her front legs along the top mesh with her back legs still on the shelf that's about 8" below the top. It honestly looks like a little Godzilla stalking Tokyo when she does that.
Go ahead and let it explore. It's a healthy sign that it's moving around and active. And also, like Roger said, if it has it's toes in the mesh and you scare it while trying to discourage it you run the risk of it getting a nail caught in the mesh and ripped off.