[Tilted Irish Kilt]

Beowulf9 :" How on earth did they know to follow that route and that it would lead to an opening of any kind at all?"

I would suggest that information is available through the inmate 'inside maintenance working gang', or an outside utility provider.
Governor Cumo said that Dannemorah was built using the same blueprint/architecture as the maximum security Attica Correctional facility .
Until they determine the exact type of outside support and route taken, the other maximum security facilities in NY are at risk.

[Beowulf9]

Good point. Yes. Must be an inside job, why would two guys in a cell know of this at all.

Come to think of it were these two guys in the same cell?