The men paused irresolutely. There were a few seconds of tense silence. Then the servants revealed themselves in their true colours—accomplices of the spy, von Eckenhardt.
Drawing automatic pistols from their pockets they levelled them at the now more than astounded British officers, while von Eckenhardt, of whose identity Terence had not the faintest doubt, wrestled furiously with his captors.
It was not compulsion that kept the Germans from using their firearms it was fear—a dread that their act would assuredly, in the event of capture, make them indictable on a capital charge.
"Shoot!" shouted von Eckenhardt in German. "Shoot, for the sake of the Fatherland."
It was Gilroy who saved the situation. Tall and powerfully built, and a prominent member of the "United Services," he was far away superior in physical strength to the denounced spy.
With lightning-like rapidity he flung his arms around the Teuton, and using him as a human buckler and a battering-ram combined, charged the still irresolute flunkeys.
Half a dozen pistol-shots rang out; not the result of a deliberate act but of the nervous pressure on the delicate trigger of one of the automatic weapons. The bullets, flying wide, chipped the oak panelling, and—omen of ill-luck to the tenant of Tuilabrail—shattered a mirror into fragments.
In ten seconds Gilroy with his living weapon had cleared the room of the enemy. The engineer-lieutenant locked the door, while Terence and the others quickly bound von Eckenhardt with their handkerchiefs.
"Stand clear of the door," cautioned Gilroy. "Now that those fellows have started to let off fireworks they might take it into their heads to put a few pieces of nickel through the woodwork. Nixon, cut off as hard as you can and bring up a file of Marines: be careful going through the grounds. The whole place is a nest of Germans—beastly cheek sheltering under good old Scots' names."
Gilroy's words, similar to those expressed by Chief Engineer McBride, showed how deeply he, a thorough Scot, resented the colossal impudence of the super-spy in assuming a respectable Highland cognomen.