But isn't the CS only supposed to cover up to the quarantine? If so, the character IC would be quite different than the one portrayed in the CS.

Edit on account of those damn ninjas: Yes, I have played characters as being mildly insane in the past. My favorite character recently was a psychopathic candy-loving pseudo-pedophile with a heart of gold, and that certainly didn't get boring at all up until the GM disappeared and the RP died. The craziness I'm thinking for this would only be a blatant disregard for self preservation and zero fear of heckling the infected at a dangerously small distance.