I have read that Lanza and a student exchanged those words. In the documentary, "Newtown", Hockley's parents mentioned that Dylan was found dead cradled with a teacher. I wonder though, was Dylan talking to the teacher at the time, or to Lanza when he entered the classroom?
It wouldn't surpise me though, as Jesse yelled "Run" (before he was shot) whilst Lanza was reloading his gun. But if this is the case, why didn't Dylan try and escape if they were in the same area?