First, this picture put out by the Newtown Bee, of the kids being lead from the school might quite possibly be the biggest farce of all, or point to something that no one wishes to admit:
[link to poietes.files.wordpress.com]
As a reference point, look at crying girl in the middle with the blue top on, just above her head is a white SUV, most likely a 2012 Chevy Traverse: [link to www.coolestcarever.com]
In order to establish exactly where this picture of the children was taken, we need to look at an arial view of the parking lot: [link to www.dailystar.com.lb]
and again, notice the white Chevy Traverse, second row from the school at the top of the row.
In this diagram of the school, the white Traverse would be just under "f" in firehouse: [link to usahitman.com]

Now that we have established exactly where the white vehicle is located we can now locate where the line of children were when the photo of them was taken. In this arial photogragh: [link to www.dailystar.com.lb]
at the lower right side you can see a directional arrow painted on the pavement. If you follow it in the direction it is pointing it actually intersects with the front door. Now, find the end of that arrow, the end opposite the point. Now, go straight up from there one car length- that is where that boy in the front of that line of children's left foot meets the pavement. Crying girl is just to the right of where the pavement goes from lighter to darker. That line of children runs parallel with that arrow on the pavement.
Again, in this diagram: [link to usahitman.com]
the corner of the school, or the "i" in principal, points directly north, so the arial photograph of the school I have supplied was taken aprox. 3:00 pm for the shadows of the cars to be perpendicular with the front of the school.
Sooooo....we now know where these children exited the school...the fricken front door!! This was supposedly where all of the shooting/killings took place, right? So you have, allegedly, shell casings (by the hundreds), broken glass, blood, your principals brains (who was killed exicution style), bodies, and all out carnage (shooting spree bodies: [link to www.documentingreality.com] )
...why in fact, an active crime scene, and what do they do? Parade the kids right through the middle of it to get out of the school?? "Put your hands on the kid in front of you and close your eyes???" Just step over your principals brains though!??
The only conclusion as to why they wanted 450-500 kids to exit through the front door, right through an active crime scene is because they did not feel that the southwest or south east exits were safe.

Here is ABC news timeline. It is insightful as you can goe "inside" the school and imagine it as it "allegedly" went down... [link to poietes.files.wordpress.com]