so a few things, just to demonstrate what I mean...
the spell she chooses is largely influenced by your distance from the boss
the three meteor spell is actually one of the BEST spells she can select (best for you, to be clear)
if you are patient, you should never be at any risk from the spiders
the first two are the most important. those points kind of demonstrate the difference between someone who knows the fight and someone who doesn't. if you think she's just randomly selecting meteors, you're wrong. she's likely doing it because you are hanging back too far out of her range to cast her other spells. and if seeing the meteors is a bad thing, it shows that you haven't learned the correct time and method to engage her. otherwise you'd be happy to see the meteors.