If you ignore him for a while, he should come out the other side of the tent, or you can reset his location hex editing a file in the save folder.
Teleporting anywhere (via hex editor) - there are 2 posts on BF merchant teleporting; the second may be a little more clear
If you don't want to wait, or he isn't coming out fast enough, and you are not comfortable hex editing, you can zip the data.000 file from the latest save folder (from a save in the BF) and email it to me (raze@larian.com).