Sure, they are large and unfriendly and have scary teeth, but they are not poisonous. That would just be excessive. Jann's eye will not suffer (extra) damage.

Emmalina is setting no records for fine swordsplay, and she's certainly not capable of fending off the spider, much less killing it. On the other hand, she is waving a sharp metal object with terror-powered force, and it's sufficient to keep the spider from jumping her outright. She's starting to get a little winded, but the adrenaline's helping. "Knife's keeping-" stab, "-it off-" slice, "-for now!"