This barrier seems to be tricky. In powers, it says "if defeated, add 1d4 random weapons from the box to your hand. I undefeated, you may banish this barrier".
Since it does not say so, I presume that upon defeating this barrier, a character will throw a dice, pick a few weapons from the box, and then... shuffle the card back in the location deck? I presume, this would be the normal handling of a barrier; but, isn't it a bit of a cheat in the game? You can have a character with decent Disable (say, Merisiel) rummage through the weapons box over several turns, collect all the magic weapons from the box, and then divide the plunder after the end of the scenario (not even necessarily winning it...)
Am I missing something about this Large Chest?