Steve really isn't even conscious of why he stops. He just does, quite suddenly. The concern to check on the man is still there. But by the time Steve notices he's stopped moving, he's already able to again.

Weird, but he hardly even notices because he can move almost immediately again.

"No problem. I know you didn't mean to be short. It's normal to be upset. I was." He still is, if he's honest. "There's a couple people who specialize in portals and doors in between worlds. I have one of their numbers? Let me try to call him."