Thanks for the reply. This is a group build. I got the idea from NTPGod (https://karl.gg/profile/10533#/), with whom I played the first versions of these builds on Haz9x2. Check out his profile.
As you have already discovered, the driller relies on his team mates to fire things up. With help of his teammates and burning goo, enemies can be temp shocked multiple times a second, which leads to astronomical dps.