 The officer, Burt Burch, had a set routine, and the convicts had attacked Miller while Burch was away.Coy, as a cellhouse orderly, had over the years spotted a flaw in the bars protecting the gun gallery, which allowed them to be widened using a bar-spreading device consisting of a nut and bolt with client metal sleeve that moved when the nut was turned by a small wrench.Coy thus managed to spread the bars and squeeze through the widened gap (Coy starved himself in order to fit through the space between the widened bars, which was still relatively narrow) into the temporarily vacant gallery and to overpower and bind Burch on his return.