I had no idea it would spread so far. I agree the two items you mention are too powerful. That was a mistake. The whole point of the Test of Resourcefulness was to force the player to do something other than fight these guys. The easy way is to take the secret passage.
Most people do a trick involving going in and out of fight mode.
I deliberately made the mission hard to find, and the initial dialogue and descriptions reflect this. Very few people have had any real trouble figuring out where they should go. I liked the idea of making it non-linear at the start, especially since it gets quite linear internally a couple of times. And there are so many random encounters with thieves and lizards that I got complaints about it. Perhaps the party you used was not medium level and they fled.