You chose. You said in post #1,320, when prabe asked to clarify what traps the assassin was checking for:
Of course, as it was clearly stated that Wizard was on the road away from the 2 Sims in the Sanctum for some reason, the sorcerer needed to be with the wizard to actually cast dispels on him as you claimed.
You never mentionned purple worm before. That would be DM fiat and break the rule of no magical items. Besides, you never mentionned casting freezing spheres in this fight.
THe simulacrum escapes, provided the sanctum wasn't blocking teleportation. Not that Dimension Door doesn't allow carrying other creatures, so the sorcerer stays in the sanctum.