Grissom asked Sara to stay in Vegas she didn't want to stay, Sara wanted Grissom to take a trip to the Galapagos Islands, but he didn't want to go. then he kind of said he wanted her to break up with him. the last we saw of Sara was her packing her bags.
Interesting, is all I'm going to say. I haven't seen the ep yet though
I thought she was in 3 eps then more later on (possibly not, maybe it's just 3 overall)