Hey SE, here's an idea.

[Akujin]

Instead of having a dungeon remain open for a period of time after the last person leaves, how about shutting the instance down WITH the departure of the last PC in that particular instance? This way..

1. DF becomes less strained by keeping a reserved instance open that no one is using.
2. People dont get sucked into an instance, thinking they are joining a run, only to find themselves all alone and hoping that 3 other people may show up and decide to run it midway.

I will say, that there have been times that I have dropped in midway through AK and managed to clear it with 50 minutes or so left on the clock, on the circumstance the other 3 players happen to be very well skilled themselves. However, it would be rather nice if the instance would just shut down itself as the last person leaves it altogether.

[pandabearcat]

Well, I think the better solution is to prevent people from joining if

1. There is less than 10 minutes on the clock.
2. The last boss has been killed.