So Calhoun industriously concentrated his fire on the man trying to get above him. He was behind a boulder, not too dissimilar to Calhoun's breastwork. Calhoun set fire to the brush at the point at which the other man aimed. That, then, made his effort useless. Then Calhoun sent a dozen bolts at the other man's rocky shield. It heated up. Steam rose in a whitish mass and blew directly away from Calhoun. He saw that antagonist flee. He saw him so clearly that he was positive that there was a patch of blue pigment on the right-hand side of the back of his neck.
He grunted and swung to find the third. That man moved through thick undergrowth, and Calhoun set it on fire in a neat pattern of spreading flames. Evidently, these men had had no training in battle-tactics with blast-rifles. The third man also had to get away. He did. But something from him arched through the smoke. It fell to the ground directly upwind from Calhoun. White smoke puffed up violently.
It was instinct that made Calhoun react as he did. He jerked the girl Maril to her feet and rushed her toward the Med Ship. Smoke from the flung bomb upwind barely swirled around him and missed Maril altogether. Calhoun, though, got a whiff of something strange, not scorched or burning vegetation at all. He ceased to breathe and plunged onward. In clear air he emptied his lungs and refilled them. They were then halfway to the ship, with Murgatroyd prancing on ahead.
But then Calhoun's heart began to pound furiously. His muscles twitched and tense. He felt extraordinary symptoms like an extreme of agitation. Calhoun was familiar enough with tear-gas, used by police on some planets. But this was different and worse. Even as he helped and urged Maril onward, he automatically considered his sensations, and had it. Panic gas! Police did not use it because panic is worse than rioting. Calhoun felt all the physical symptoms of fear and of gibbering terror. A man whose mind yields to terror experiences certain physical sensations, wildly beating heart, tensed and twitching muscles, and a frantic impulse to convulsive action. A man in whom those physical sensations are induced by other means will—ordinarily—find his mind yielding to terror.
Calhoun couldn't combat his feelings, but his clinical attitude enabled him to act despite them. The three from Weald reached the base of the Med Ship. One of their enemies had lost his rifle and need not be counted. Another had fled from flames and might be ignored for some moments, anyhow. But a blast-bolt struck the ship's metal hull only feet from Calhoun, and he whipped around to the other side and let loose a staccato of fire which emptied the rifle of all its charges.
Then he opened the airlock door, hating the fact that he shook and trembled. He urged the girl and Murgatroyd in. He slammed the outer airlock door just as another blaster-bolt hit.
"They—they don't realize," said Maril desperately. "If they only knew—."
"Talk to them, if you like," said Calhoun. His teeth chattered and he raged, because the symptom was of terror he denied.
He pushed a button on the control-board. He pointed to a microphone. He got at an oxygen-bottle and inhaled deeply. Oxygen, obviously, should be an antidote for panic, since the symptoms of terror act to increase the oxygenation of the blood-stream and muscles, and to make superhuman exertion possible if necessary. Breathing ninety-five per cent oxygen produced the effect the terror-inspiring gas strove for, so his heart slowed nearly to normal and his body relaxed. He held out his hand and it did not tremble.