Why is Rachel McAdams drenched in blood and screaming her head off?!

Show of hands: How many of you have gone on a business trip and threatened your boss with a razor-sharp spear? Hmm, just me. Well, I’m in good company because Rachel McAdams has done that too, and she was in “The Notebook” which is a national treasure!

The point is, Rach (as I call her) is getting primal in her upcoming dark comedy “Send Help” with Dylan O’Brien and we have the gloriously demented new trailer. Think “Horrible Bosses” meets “Lord of the Flies” with a dash of Stephen King’s “Misery.”

Sure, the movie could have easily taken a page out of the Hallmark Channel’s playbook: girl meets boss, girl hates boss, opposites attract and they fall in love. But this is a Sam Raimi directed movie. AKA the guy behind the “Evil Dead” franchise.

So, instead, of a meet-cute, we get a plane crash on a desert island and tension you could cut with a broken coconut shell. Entertainment Weekly says “the colleagues descend into a battle of wills and wits. Who will make it out alive?” Ooo, good question!

As soon as Linda (McAdams) utters “I don’t think we should ever leave” while laughing like a drunk hyena to Bradley (O’Brien), my money’s on her surviving. But how would you do in an anxiety-inducing castaway scenario?

I think I’d befriend a volleyball and name it Wilson. We chat for hours about our hopes and dreams, share our inner-most secrets, and build a life together. Then one day I’d come back to our cave and catch Wilson in bed with a beach ball. Oh, the humanity!!!

“Send Help” hits theaters January 30.