Not sure if this is happening on all servers, but about 80-90% of the time when doing a Headless Horseman run, anywhere between 1 person(tank usually, because they click the pumpkin) or the whole group will have a client crash / Disconnect happen to them. It makes running HH not fun really . Well anyway this usually ends up in at least one person dropping group. So, if you are the first one back in after everyone DCing, you will most likely get dungeon guide and be able to invite your friend, then votekick the others that stay DCed. I found this very helpful in getting my lowbie friend into the run(lvl 74 so can't queue for it). One time I had every person in the group leave but one, so I invited my friend, dropped group, got on my lvl 72 and got invited. Then just kick the DCed people and re-enter queue (yes it lets you even if you are BOTH under the level requirement, as long as you are already inside and "in progress"). You won't get your loot pumpkin, but you can at least need on some rings for when you hit 80. Also this makes it fairly easy to get the achievement on a lowbie alt.