Twice in a row I wasted 200 currants by joining Depth 8. The first time, it was a group of low levels who were actually leaving the place, so I went with them and tried again. This time, there was a group meant for Depth 8, but I think some guy rushed to the lift and went on without us (or I was kicked), so I was automatically teleported back to town within seconds. I think this is a bug because not getting a refund could cause me to go broke, and would force me to go out of my way to get back on track - which would be to go to the beginning of the map and waste my expensive energy to earn the few currants I need for Depth 8.