I think now, with this revelation from the press conference, it is obvious why he chose the Amish school - thinking it would allow him time to do his evil deeds before anyone got to a telephone.
I agree. At the presser, the PSP Col. stated several times that it was the 'accessiblity' of the school, not the Amish nature that made it the killer's choice. No access to phones. No way to call for help to stop his plan. The ultimate in evil.
That makes my blood run cold but I totally agree. Tactical error on his part but too bad for him. At least now he has a LOOOOOONG time to think about what he did.