How much that catches him off guard is enough to trigger Steven's instincts enough that, for a moment, a shattered portion of the top of the bubble forms - just enough that the shoved bubble can fall and bounce backwards and away from the wall of gas. He can't control it when his mind is caught up in the fear of the moment, and the environment is already shifting and changing as he moves.

It suddenly seems like it's falling. It bounces once, twice, and then shatters. By the time he collects himself, he can't even see the scene he just fled from anymore.

"DAD!"

And that's the end of it. For the moment, he's escaped, but Greg is gone.