The turnstyle on the entrance in the distance was only added after a riot in 1988. Before this there was no turnstyles, so there was no limit to the number of prisoners that could re-enter the cellblock at a time – this allowed 70 violent prisoners to rush into the block and join in with the riot. The addition of the turnstyle would mean the numbers of prisoners entering the block at a time could be slowed down, preventing future attacks escalating so quickly.