Can I use a narrator to portray another character in a script?

So I'm writing a script for the first time and my script has 4 characters.

I want to introduce another character, but I want to express the dialogue of this new character with the narrator, so is being spoke from 3rd person and not 1st like the other 4 character if that makes sense?

I want this new character to be a killer, he’s a hunter in the woods.

So could I use dialogue like this? This is a part taken from my script

From a far they spot someone walking in the distance.

Michael: Look there’s someone there

Becka: Oh good maybe he can help

Ellie: Do you really think we should approach him? I mean we’re in the middle of nowhere, we don’t know this guy.

Michael: Relax what’s he gonna do? There’s four of us and one of him, I’ll ask him for help.

Michael jogs towards him, while the other three are a distance behind

David: I think that’s the hunter guy that was shooting deer a couple hours back, he’s holding a rifle.

Becka: WHAT? So that guy’s got a gun!

The hunter with the rifle aims the gun at Michael

Seconds later Michael YELLS the words.

Michael: PLEASE DON’T SHOOT!

Sound: BOOM BOOM (The sound of gunshots) as the hunter pulls back on the trigger and kills Michael.

Becka: SCREAMS OH MY GOD MICHAEL

David: RUNNNNNNNN!