 The van was ordered to stop by the armed INLA men, however, the driver, John Park, thinking that he and the other officer were about to be taken hostage, intended to accelerate through the partially opened gates in a bid to escape.He was prevented from doing so when the gates were automatically shut.The other prison officers stationed at the forecourt gates had spotted the men on the roof, and assuming there was a prison escape in progress, activated the alarm system.