...and it was a Precise Destro Staff, much to my dismay. :'( I was unable to loot it and was then kicked to log in screen.
When I came back into the game, I had no portal to get back into the chest arena, and there was no chest on the room (as my guildmates said there should be in these cases). The staff was also not in my inventory. I've submitted a ticket along with proof that the staff was in the chest (via screenshot), and support has told me they have no way to help me recover the staff.
Has this ever happened to anyone and did you manage to solve it? Can support really not do anything regarding this?