Here are a few things that I have found regarding befuddlement gas.
If a monk is hanging onto a ladder or bar, the gas does not work. For instance, if you gas a monk next to a ladder and another monk is coming down the ladder and is blocked by the monk that was just gassed, the monk on the ladder will / may get you if you try to go by him.
You can not dig under a monk that has been gassed.
Sometimes if a monk walks into a gas cloud that is over an excavated pit, the monk will not fall in, he will float over the hole.
If you gas a monk that has just been trapped by a snare, the monk may be freed and the snare will disappear.