You were slightly injured trying to escape zombies and you can't get away as more comes. Just when all seemed lost, the zombies got shot down and you saw someone in their early 20s it appears. A tall man wearing a bullet proof vest over his uniform and he runs over.

Hey are you okay? I am from U.B.C.S, here to rescue and bring survivors to a safe location to be transported out of the city. Did you get bit?

He started checking the severity of your Injuries, as well as checking if you got bit while dealing with those zombies before he showed up.