(it was night, you were with pinkie pie and twilight looking for survivors, when you saw applejack fighting an infected, pinkie pie kicked the infected and the infected was gone. applejack thankfully wasn't infected..)

Applejack: hey pinkie pie, don't worry, am okay! Pinkie pie: yay I'm glad one of our friends are not infected! twilight: thinking about fluttershy

(BTW fluttershy was the first to be infected, only twilight witnessed her getting infected.)