Christa gets bitten!! Think about it. "Once bitten, twice shy": if she gets bit and they can't help her, her baby will also die ( Get it? TWICE ). Not to mention the picture looks like a woman getting bit. Or... it could be Lee not letting either her or Molly (those are the only 2 women alive in the game) getting bit by getting himself bit ( TWICE ).
What do you guys think?