Acacia doesn't leave the trees then. A fight in open terrain is a fight she would lose. Sure, she could possibly get in one surprise hit on the sleeping beast, but after that, the beast would have the advantage. And without knowing how fast it moves, she doesn't know if she could get back to the trees before it caught her.
Instead of engaging, therefore, she retreats back into the jungle and begins to set up an ambush for the creature. How elaborate it is depends on how much time she has - and her player will need to do a bit of googling to describe what sort of traps she's able to create.
The beast seems quite deeply asleep. It won't wake up anytime soon unless disturbed, so Acacia will have plety of time to set up her traps.
My FFRP characters. Avatar by Kid Kris. Sigatars by Gulaghar, Kid Kris, Zefir and billtodamax, respectively.