The prisoners now moved swiftly. They took the cell keys from the dead bodies and released the other prisoners, all of whom were armed. Already there was a tumult in the charge room, and the sixteen, with Mecklen, burst in upon a dozen or so officers, only two of whom had had the time or forethought to arm themselves. The two died in their tracks before they had time to fire a shot, and the others paused aghast. In another second the seventeen men were streaming across the road to the waiting lorry, the hind-most firing random bullets backwards to discourage pursuit. They piled in, and the lorry moved off, gathering speed, to the accompaniment of a final volley from the escaped prisoners. Before the pursuing constables, who were now armed, could return the fusillade, the lorry had turned a corner and disappeared. The Flying Squad and all reserves of every Division were called out, and those first on the scene commandeered cars and taxis and dashed off in chase, but the seventeen, with their lorry, got clean away. As has been stated, the P.C. at the door had not taken much notice of the lorry, and its number plates had been so caked with mud as to be indecipherable from across the road, in the dim light. And, standing midway between two street lamps, at night, one big lorry looks very much like another--the doorkeeper was unable even to identify the make with certainty, although he thought it looked like a Rossleigh. But the most remarkable feature of the crime was its execution. For one thing, it proved that the Alpha Triangle had an unusually accurate knowledge of police station routine. In the first place, ordinary "drunks and disorderlies," being apparently harmless and charged only with minor offences, are not perfunctorily "fanned." As was demonstrated at the subsequent inquiry, it would have been possible for a man not suspected of carrying arms to have concealed a small automatic pistol in a holster strapped to the small of his back, with little risk of it being discovered in a more or less formal search; and in the absence of definite information this theory is the one which is now universally admitted satisfactorily to account for the Triangle's success. Secondly, the locks of the cell doors, and those of the doors leading from the charge room to the cells, can only be opened by a special manipulation of the keys which is a police secret; yet the prisoners had clearly been well instructed in this trick beforehand by someone with an intimate knowledge of that secret, for there was no delay in liberating the occupants of the other cells.