Sime was able to take the neuro-pistol. He knew what was expected of him, and strove to collect his faculties so he could obey orders. He crawled a little way into the lock, where he could be in comparative darkness, setting the little focalizer wheel at the side of the pistol for maximum concentration. Such a beam would require good aiming, being narrow, but if it touched a vital center would be infallibly fatal.
Meanwhile Tolto appraised one of the posts on the roof. It was firmly set in masonry, but he found he could loosen it a little by shaking it. Presently he had it uprooted. It made a splendid battering ram, a war club fit for a giant such as he.
"Here they come!" Sime croaked, and, peering around a corner, took careful aim at the foremost attacker. At the first whispering impact of the beam the Martian sprawled, dead.
The soldiers were caught at a disadvantage. They were expecting club or fist, but not the neuro-beam. Nevertheless Sime had no more easy opportunities. The Martians flung themselves down behind the bulge of the curved stairway, and the air became acrid under the malignant neuro-beams.
None of them reached Sime directly, but the stone walls reflected them to some extent, and even under their greatly weakened power he become cold and sick.
The situation was by no means to his liking. There were other weapons to be reckoned with, and he tried to keep consciousness from slipping away from him. When at last his breathing became easier and his diaphragm moved without pain, Sime knew that danger was greatest. For this relief meant that the Martians had withdrawn down the stairway.
"Good-by, boys!" he thought, as he sprinted up into the comparative safety of the open. He motioned to Tolto, who stood hopefully waiting with his great war club, to stand clear.
There it was! Sime saw the faint phosphorescent reflection against the stone where the stairway curved. He did not wait to see the tiny pellet of the atomic bomb floating up, but threw himself flat on the roof, tugging at Tolto, who understood and followed suit.
Even lying prone, and below the edge of the explosion cone, they were nearly blown off the roof. Though no larger than a pinhead, the bomb had the power of a thousand times its weight in fulminate of mercury. When the rain of small stones and dust had subsided, they rubbed their eyes and saw that the airlock was no more. In its place was a shallow pit, ending with the top of the battered stairway.