Christian, how do you use the sewer exploration table to locate the Worm Sorcerer? Just keep rolling a d8 (and dealing with any encounters it presents) until you get an 8, or do you follow the lines that connect the numbers?
It's basically your choice. The map (lines) was just a fun little idea, not intended to be taken too seriously. My recommendation would be to just roll for a few encounters, maybe three, and if the 8 doesn't come up, it is the next one :)