Hmmm, thats not entirely correct... If you kill a boss with reward system (oberon, for an example), yes, in theory you could loot your reward bag right away... But if you didn't deal the most damage (if someone else "won" the boss), you still have to wait 10 seconds to open the boss body... He still have regular loot (gold coins, etc...) which is "owned" by the winner... After those 10s you can open Oberon's body and then open your bag