Take a look at the RtL encounters. More precisely, check the attack types of the leaders and their minions (if any).
Count how many are (almost) completely made up of monsters that use melee attacks. That's right: 11-13 out of 29.
Then bring to mind the horror that is Zyla.
Ghost. Lovely isn't it. Immune to adjacent melee.
"That's ok, I have melee-based monsters with Reach! Hah! That'll teach her".
And that's when Zyla ends each of her turns in a tree space. Shadowcloak + Ghost.
Combine that with the other 3 heroes in her party fleeing the map (possibly after killing the only non-melee monster in the bunch), while Zyla stays behind to mop up.
Other than wanting to know what genius conceived that obnoxious gnat of a hero, I don't really have a question. Guess I was just looking for a place to vent frustration over a situation where it becomes impossible to damage a hero.
No really, what is supposed to happen? Concede 1/3 of the encounters upon drawing the card?