Be bitten?
I've been thinking about the location of the walker at the end of episode 4, and the fact that it's right next to clementines dropped radio makes me think she was attacked by the walker, dropped the radio in the struggle/in panic, and then was rescued by the radio man, who proceeded to kidnap her. However, considering the unlikeliness that clementine could have held off the walker long enough for the radio man to intervene, it could be possible that she was bit.
Thoughts on this theory?