From the book:
"Your party is battered and bruised, but the fight is not over. Whatever now rules in this tower is likely on the upper level. While it is tempting to leave now with the gains you have made, it would then be left to some other group to come and finish the job, and who knows what evil might be done here in the meantime. Readying your weapons, you advance up the stairs."
Half of the group coming out throught the trapdoor.
Turn 2. My archer, activated by the ranger, shoots and kills one gnoll archer before he could act, but later is wounded by another gnoll archer. The rest of the group arrives.
A phantasmal green fire comes from the beacon tower of Tor Dargos and some members of the party get poisoned (the ones with yellow markers). The barbarian uses the fairy dust gathered at the lower level on his sword, which helps him to wound the shadow knight. The dog fails to hurt him.
On the next turn the ranger charges the shadow knight and manages to kill him with the magic sword he found downstairs.
Tor Hammel has also been lit with evil green fire! The archer activates first again and kills the last gnoll archer. Seeing this, the surviving gnoll falls back in shock.
He is finally killed on turn five and the encounter is successfully over.
I was lucky to find something to help me fight the magic resistance of the shadow knight and thus killing him so soon. The rest of the encounter was a walk in the park. I've got the maximum XP for this encounter, 62 XP points!