And Then There Was One

You take the shot guns and bullets, although you have no idea how to work with a gun. And there are only 7 bullets so if you miss any shots, it may be no help. You cell phone rings and it says Abby. You open your phone and yell out "ABBY! ARE YOU THERE? Where are you?!" All you hear is screaming that sounds like Abby and then the phone hangs up. A following text message says, "Go to Room 227 and kill the person in there, if you want your sister back."