I need an unexpected twist in my story?

The chupacabra comes out of a cave and grabs them both and takes them to a secret world filled with scooby doo and shaggy clones.

Instead of riding a Fellbeast to Mordor to dispose of the ring you can instead spend about 12 hours of screen time walking there.

They get kidnapped and are sold into sex slavery. One of them dies and the other escapes but is lost in a foreign country and she doesn't know the language.

The one trips down a cliff and dies, becomes a ghost and later the other one finds him in his house and the one who tripped blames the other and works to haunt him to misery.

One of them gets a case of Deja vu

One punches the other in the face without provocation.

take it from there.

Both are the same person.

they crash... they black out... they get kidnapped.. there ya go, 3 extremely interesting paths, have fun.