So briefly, if I understand well:
If at every 20000 game turns excepted for the very first one (0), a random number generated (from 0 to 1999) is equal to 0, a random number from 0 to 9 is generated. If that number is 7, then you get "Your pants are definitely too tight". Otherwise, you get one of the other silly mentor quotes, excepted for speech 98 because of the number 7 above (which is weird, should be changed). Am I right?
Hah, I was so wrong when it was related to number of creatures and rooms.