We think it happend to everyone in Knight, you get out of ED after 5 mins cause mages blink to deva en kill it right away. And we have no clue who those mages are except the pt and they not gonna report those mages for that since they where in the party also. A number of people suggested ideas to stop them. Disable mage TP(effects the PVP). Disable blink(Many mages WH). Make deva appear after last boss is killed. Put aggro monsters in the walls.
Another thing that would improve ED is taking out the draki items(knight gold). Maybe you have lost count on how many ED's have been screwed up because of one person looting a draki item to another person. It get people angry and people start leaving. Then the ones that are left can't finish it cause it takes too long time.
Best would be to edit the map and eg is to make more solid walls, but yeah that most likely wont happen Anyway a decent party can get to deva in 10-15min, so you don't have to stay for an hour. Unless it comes down to fighting and the enemy doesn't let you kill deva ofcourse. Also we think it was said before that this wallthingy wasn't seen as a crime or being punished. You can buy Knight powerleveling on our site as well.