Go into instances prepared! Always make sure you have a good supply of
consumables, in this case have a stack of soder colas on hand. If you leave the
instance prior to completing the mission, you'll have to start it over again.
After speaking with Parasite, attack and kill the meta-powered students found
along the back walls of the Library. Once you have captured your first four,
speak to Parasite then follow him north to the office and labs and capture
another four students. As you go be sure to grab the box of goodies in the north
eastern corner of the instance. Now that you have turned all the students
outside the force field, it is time to go after Powergirl!
To be able to do any damage to Powergirl at all, you have to turn the students
in the ampatheater first. Powergirl lets off a big AOE stun followed by
additional damage, so it is best to stay out of her way completely. Snatch the
students while avoiding Powergirl until you have gotten enough to weaken her. At
this time, Powergirl will become vulnerable to damage but she still fights back
so be careful. You are locked into the room and you won't tick up in health
while in battle, so be sure to have a full stack of soder colas on hand because
you will need them. If you have ranged skills, use those. Parasite and his
minions will do consistent damage to Powergirl so you really only need to not
die while continuing to assist Parasite in the fight.