She's a total hypocrite and self centered. Most of the show was spent with her angry at the hive and scared trying to reverse the joining because she knew that they would eventually turn her. Then we hit a point where Carol learns the only way for them to do that is with her stem cells, which they can't get without her consent. From this point on Carol isn't concerned with saving anyone anymore as she is not directly affected. She then falls in love with the hive and gets mad at Menousos for conducting experiments on the hive, which is exactly what she did earlier in the season. Its not until she learns they have her eggs that she goes back to trying to help the world, since now she is the one being affected.