Temporary item bank for rare items

[Lambdafish]

So I just got out of a Battle at the Big Keep where I had a Bartz card hit the floor because my inventory was full. I didn't set out to get the card, it was a roulette, so I was there for the xp, and given how rare it is, I wasn't expecting any loot (before anyone says trololol make sure you have space next time).

Given that I may never see another Bartz card, can we please have a temporary item storage that lasts until the end of the instance for these kinds of things (cards, primal drops, sheet music) so that they don't immediately hit the floor if our inventories are full. Also, if everyone leaves a dungeon/trial except you and you have a full inventory, the chests contents also immediately hit the floor, this feature will also alleviate that.

Edit: Please keep the discussion on the feature, not my problem, I've gotten over the fact that the card hit the floor, and I know it's my own fault, but that does not change the validity of the feature that I am requesting.