WHAT WOULD YOU DO?

I just started writing another post and while thinking back over things I decided that this was a call that I had not shared with you all when it happened that may give a small perspective of the things that a police officer deals with from time to time, I will post this one and give you time to respond if you want to and then give you the rest of the story.....

You get dispatched to a frantic unknown 911 call, the dispatcher tells you over the air that she really doesn't know what is going on but she thinks that it may be someone stabbed and the intruder is still in the house.

When you arrive there are frantic adults and kids all over the place, crying and urging you inside. In the panic, you get separated from your backup officer but there is an adult female who is charging towards the door and you have to keep her safe, you need to make sure she don't go inside. You catch up with her at the doorway, as you look inside, you see 3 people all covered in blood lying motionless on couches just inside the doorway. You advise dispatch of what you see and request additional units to the scene.

What you see is:

• An adult  female with a bullet hole right under her eye on the couch just inside the door covered in blood.
• An adult male with what appears to be a bullet wound in his mouth lying on the couch to the right of the female covered in blood with a handgun lying in his lap.
• A teenage male about a foot away from the male with the gun on his lap, covered in blood, motionless with his hands behind his head as if possibly clutching a wound, but no visible wounds apparent aside from him being covered in blood. When you check his pulse, his eyes go wide and appear to be dilated, he will not respond to you continuously yelling at him to "show me your hands" he is at first silent, almost catatonic but when he begins to speak, everything he says is loud incoherent babbling and he is again as I said before about a foot away from a loaded handgun.
• You do not know if he is a third victim (and there is possibly someone still inside the house) Although backup units are now on scene and along with you trying to make heads or tails of the situation.
• You do not know if he is the gunman who is currently on drugs or drunk and the gun is lying a foot away from him.
• You do not know if there is some other reason for this teenage boy to be acting this way.

You have about 1/1000's of a second to make a decision and these are the facts that you have before you, What do you do?