I did think the same thing when I first saw it, but my guess is basically he just got out before it got completely swamped and apparently just ran the whole way back. I get that from when we see his first appearance and he is just running in front of them. So that's my guess
As for the episode, while it wasn't bad, it was definitely a come back down to earth show compared to the others this season. I guess it needed somewhat of a slow down episode at some point and this was it. I still liked it as it had some good parts, but overall, not up to the rest of the season