Character mistake: After Nick kills Calvin, and Travis arrives, Nick calls Travis "Nick" before correctly calling him Travis in his next line of dialogue.
Blood Drive - S2-E6
Character mistake: Zayday makes incorrect statements about blood types. She mentions that, since Chanel #5 is type O-, her parents must also be O-; in actuality, they could each be type A or B (genotypes AO or BO, respectively) and could also have Rh+ blood as long as they also carry the recessive Rh- allele. Zayday also says that the child of two O+ parents must be O+, but actually the child could also be O- (again, if the parents carry the Rh- allele).
Suggested correction: Travis is the one who says "Nick".