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 tensed. He felt extraordinary symptoms like an extreme of
agitation. He swore, but a Med Ship man would not react to such
symptoms as a non-medically-trained man would have done. 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