Started the day off with a traffic collision with extraction. It was in the middle of no where with a extended response (about an hour or so). While scanning fire we hear a eta for Mercy, ok cool. Arrived on scene and saw the two patients. 1 sitting on the concrete k-rail and the other fully immobilized. Wondering to myself why one patient is fully immobilized, the car doesn't look all that damaged. Driver fell asleep, hit the guard rail and the suv landed on top on a water barrier. Nothing too crazy, driver self extricated and the passenger was helped out by fire. Couldn't really hear the story on the passenger but visually there's no trauma, couldn't hear any assessment findings from fire. Driver has a cc of shoulder pain (from the seatbelt). Anyway, passenger is flown and enjoy route blood pressure drops and the flight crew administers txa. When we arrive at the hospital (72 miles later) we find out that the passenger has a lacerated liver. Real cool call, wish I could've heard the pass down on the passenger all I know is no one suspected an internal injury and that fire was basing it off the mechanism and that the passenger was sleeping in the back "restrained".