What are some of the thoughts Henry has as he prepares for combat?

Henry was afraid he'd run from battle.

However, he perceived now that it did not greatly matter what kind of soldiers he was going to fight, so long as they fought, which fact no one disputed. There was a more serious problem. He lay in his bunk pondering upon it. He tried to mathematically prove to himself that he would not run from a battle.

Previously he had never felt obliged to wrestle too seriously with this question. In his life he had taken certain things for granted, never challenging his belief in ultimate success, and bothering little about means and roads. But here he was confronted with a thing of moment. It had suddenly appeared to him that perhaps in a battle he might run. He was forced to admit that as far as war was concerned he knew nothing of himself.

Henry panicked, believing he might possibly disgrace himself.

A little panic-fear grew in his mind. As his imagination went forward to a fight, he saw hideous possibilities. He contemplated the lurking menaces of the future, and failed in an effort to see himself standing stoutly in the midst of them. He recalled his visions of broken-bladed glory, but in the shadow of the impending tumult he suspected them to be impossible pictures.

He sprang from the bunk and began to pace nervously to and fro. "Good Lord, what's th' matter with me?" he said aloud.

He felt that in this crisis his laws of life were useless. Whatever he had learned of himself was here of no avail. He was an unknown quantity. He saw that he would again be obliged to experiment as he had in early youth. He must accumulate information of himself, and meanwhile he resolved to remain close upon his guard lest those qualities of which he knew nothing should everlastingly disgrace him. "Good Lord!" he repeated in dismay.

Henry looked toward battle with apprehension.

As he looked all about him and pondered upon the mystic gloom, he began to believe that at any moment the ominous distance might be aflare, and the rolling crashes of an engagement come to his ears. Staring once at the red eyes across the river, he conceived them to be growing larger, as the orbs of a row of dragons advancing. He turned toward the colonel and saw him lift his gigantic arm and calmly stroke his mustache.