I know how you feel. Went to a PUG delve and someone die and instead of HP'ing they just went AFK to screw ppl over their lot. I lost an Airlixir +1 in that PUG. It's unfortunate that crappy players like that exists (just like those other crappy players that didn't even have zone access for a Delve and took 45min+ to get there and the lead refuses to replace them).

The only thing that you can do:
1. If it's a PUG, add those players to your Do Not Invite or Warn Lead list.
2. If it's your own LS, time to re-educate your LS-mates about the old Dynamis last 3 min rules.