I've seen no less than 5 different accounts of kids running from the school:
1) Rosen; claims 6 kids were in his driveway
2) Marilyn Gudsnuk: Saw 2 boys running screaming down the sidewalk (what sidewalks? there aren't any) and a man driving by "looking" for his boys.
3) Unknown woman in Van: Picked up 5 or 6 kids on Riverside who took them to the police station. [link to transcripts.cnn.com]
4) Barb Sibley: Saw "8 or 10" kids running up Dickinson Drive.
5) Woman on Riverside drive saw 2 boys and 3 girls running across the athletic field on Riverside Dr. which is past Gene Rosen's if coming from Dickenson Dr.

I think that covers all the eyewitness accounts of children running from the school.