Before that we teleported our ranger to a cliff where the chest is (in the ruins where the final fight takes place) and we couldn't teleport him back. He couldn't jump to us with tactical retreat also.
That is because if you don't have far out man talent you can teleport to a destination 15m away but the target can only be 13m. So you can teleport someone to that ledge (which is 14.8m at the closest) and can't get them back.
I got stuck there also and had to reload. It is a bug I think - you should only be able to teleport 13m.
Either your character with teleport needs far out man talent or the one with tactical retreat - it works for both.
The chest always has good gear.
