So my cousin and I are questing together, him with a summoning necro and
me with my strafing zon.  We walk out of the Pandemonium Fortress, walk a
wall untill we get to the stairs to Izual's area.  Start up the stairs.
There is Izual, filling the doorway at the top, with two packs of Blood
Souls and two packs of Doom Knights behind/with him.  I could tell there
were two packs of each because some were minions and some were not - of
each.  I cast my decoy as far behind everyone as possible, but it goes
down so fast it is a waste of my time taken off of strafing them all.  I
am downing fat purps left and right and screaming at my cousin over the
phone to warcast his fire golem on the other side of them all, as well as
begging him to cast DV on those Blood Souls.
Neither of us died, but both of us sure came close several times each.  I
ended up using 8 potions, he used 6 or 7 I think (he was mostly behind me
on the stairs heh).  Thank goodness there wasn't any lag at that time. :)
I always thought 'stair traps' were when you 'ported down/up and there are
many 'welcomers', this was a different variant, but sure was scary at the
time.