Wicked Science: Fever. When Elizabeth catches a cold, the virus not only has a bizarre impact on her genius "flashes" but also begins to accelerate at a dangerous rate - and Toby is forced into a desperate race against time to save the life of his best frenemy. This is a really good episode, with some genuine high emotion and great character stuff for both leads. It's interesting that the episode again brings up the "flashes=compulsion" notion that Toby brought up toward the end of last season, here amusingly forcing Elizabeth to do nice things for people even though she doesn't really want to. More interesting is Toby's suggestion that it's just tapping into a side of her she's repressed, and specifically bringing up what she was like pre-accident. Elizabeth dismisses her former persona as "weak", but Toby insists not everyone thought that. It's a pretty creepy idea that what's happened to them has actually affected their personalities, and while Toby implying that he liked her shy, introverted pre-genius self is a nice sentiment, you can't help but think "well maybe you should have acted like that then!" Elizabeth's complete faith and trust in Toby's ability and willingness to save her is quite sweet, if unsurprising, but Toby continues to baffle me. Like the season 1 episode where he acted to save her from expulsion, this episode again indicates that his feelings for her run deeper than he wants to admit, but why? The notion that he liked her pre-genius makes his attitude to her even weirder. The episode ends with Elizabeth clearly crushing on him harder than ever after he literally saves her life, and clearly unconvinced that by his attempt to brush it off as "oh, I'd have done it for anyone!" Oh and there's a touching and funny bit between Elizabeth and Verity, where the sick Elizabeth starts to tell her how much she values her friendship, only to be interrupted, and then later denies remembering the conversation when Verity tries to bring it up after she's cured!  
 This is a great episode.  
