i am going to have to agree with heresy in the fact that there could definatly be a second person involved. i mean, if you kill two people on the 2nd floor of a dorm, its going to be really hard to get out of that dorm without having to kill more people. I've lived in a dorm, and the doors are always open people socializiing, nosey ass people poking their head out every loud noise etc.... somebody would more then likely try to stop him.
then a two hour time lapse before the next shooting........ even assuming he got out of the dorm undetected, tucked his guns, and got across campus without any problems, why would he wait two hours to start shooting? they said it takes twenty minutes to walk across campus, what was he doing for the other hour and a half?