I do not have a picture for it but... Baal managed to summon one of his vision before he got the final blow ... We all know, during "visions" baal is immortal, so how ...? Well, my guess... thorn spikes hit him before summoning was complete (???) As a result Baal was dead but his vison (duriel) was alive and kicking
If you played on TCP/IP its not hard to face similar delays (even famous black walls), also if some crowded areas gets laggy for you try to run client twice on TCP/IP and let host just be wherever in town.