They go in.
The Giant Needler is essentially a small treant without a face. It, thankfully, moves fairly slowly, and doesn't just shoot giant needles in all directions. It has two limbs that look something like arm-cannons, which it points at whatever it intends to shoot, and makes a loud rustling noise for several seconds before loosing a shotgun blast of razor needles.
Ken spends his time right up close to it. trying to slash at the limbs and 'feet', and getting needled and kicked for his trouble. At least he's wearing a helmet.
Abyssia stays a bit further back, shooting and trying to knock the arm cannons aside when the boss gears up for .
Dalton pelts it with those blue blasts, and shouts out that he'll wait for a good opening then yell at everyone to get clear.
(Two small Frost Spiders appear between gaps in the room's 'wall' of foliage. The other three don't appear to notice them.)