Level 13 LAG on two runs, have ran five times. The two runs, one was a fail, but the other was lag success.
Level 16 on no runs, have ran five times. I even run it with summoned protectors and no problems.
Level 20 one run, MASSIVE LAG. Death due to lag. A sorceror cast Dancing Ball on altar, gargoyles spawned, LAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGGGGGG. This was the unable to move lag and inability to make a chat statement other than two minutes later it might appear.