"We could try to track down the party which caused this problem in the first place, but you would be depending on their good will, as they are a bit more combat experienced. We could go to the City Councilors, but the six of them normally allows adventurers to act freely in the depths below. And then there is the fact that we would be revealing the possibility of other workshops to loot below. There are several helpful and powerful non-humans that work in those depths, and I would like to avoid a sudden surge in adventurers stomping around and looking to throw fireballs among the sewers we are employed to keep safe. The repairmen will meet you at the entrance to the Black, Section 2 sewers. As you know, the passageways below descend from the highest black level to white. The bands are Black, Red, Orange, Yellow, Green, Blue, Indigo, Violet, and White, with black being almost entirely modern sewers and white being completely a set of passageways from an older city that ours was built upon. The repairmen know the way and carry maps with them. All joking aside, your question about possibly being mutated by this thing is a good one. According to Mr. Stinks, his employer was studying the tool but never used it as he felt the danger was too great. Because of that he only has a theory on how it works. He believes that the portal that is created may be defective. Normally a planar portal is supposed to only act as an entranceway, but not transfer planar material. There are safeguards built into such devices to prevent accidents. However, he believes that the tool is defective and once the energy from the other side builds too much, it pulses forth into our world. He believes that as long as you avoid being in front of the portal when it is about to pulse, you should be fine. Here is the spare gem that can be used to seal the portal so you can destroy the device."
Saying this, the clerk slides a small, pink gem across the desk for you to take.
OOC: Hope I got all the questions covered.