I see your past this point, but for others dealing with this issue here is my advise-
If the tensioner slips out you can always use a light, magnet, and a long screwdriver to pop it back in, Ive done it many times. The main thing you want to watch out for is if the chain has jumped a tooth on the crank sprocket, then it can be a pain. Most of the time if the sprocket is close but just wont line up with the cam, the tensioner is still in its just out a bit and needs to be pried back into place.