Apparently no gunning down.
I like Jack/Isaint's call to disengage - absolutely nothing to be gained from a pitched battle with this witch, and lots of different things to lose.
But just in case things go south anyway, also activating the Flexibility focus. RAW not crystal, but I'd say its anti-get-subdued-in-melee bonus applies to being Engulfed by branches and vines...(or not?).