If you crash out of an indy or you die and the last mob is killed and don't have time to get back in (as has happened several times in the advance trial) you lose out on the reward box. As the reward box is often the main point of the indy (particularly the trials), this seems wrong.
Given the game won't let a 4th person enter if the 3rd crashes they should get their reward even if they aren't in (either dungeon or the game) when the boxes are sent.