Perforator is in basement below the waterfall, chamber is packed with mobs in the centre.
Soloing this quest, I could do without a shedload of adds.
With hindsight, it might have been a good idea to clear the chamber before starting the main quest body. However, standing at the edge of the chamber, it is easy to pick off most mobs as single pulls, just one group of three came.
The Perforator seems to have very short (or no) assist range, he wanders around and came very close to many of the clearing fights but didn't join in.
Then he was on his own and went down without much fuss.
110 Solo Mage. Air Pet EM XXI