e!" snapped Phillips. "Calm down!"

"I'll calm you down with me!" shouted the other hysterically. "I'll
_show_ you who's afraid to die!"

He ducked through the door toward which he had been backing. Phillips
lunged after him, just barely missing a grip.

"On your toes!" he shouted over his shoulder to Donna, and turned on all
jets.

But Truesdale, driven by his peculiar fury, not only stayed ahead as
they raced along the corridor, but actually gained.

He was fifteen or twenty feet out in front as they reached the midway
point. Phillips, expecting him to take refuge in the rocket room, was
completely fooled when Truesdale leaped for the ladder in the vertical
well. He stumbled, and grabbed a handrail to stop himself. The other was
swarming upward. Phillips sprang to follow.

Hardly had he climbed half a dozen rungs, however, than he saw he was
outdistanced. Truesdale's feet were already disappearing beyond the
hatchway. Phillips waited for the airtight door to slam shut. It
remained open....

Then a thrill of instinctive fear shot through him as he thought of what
Truesdale might do--probably was _doing_ at that very instant!

[Illustration: 4]

Throwing his feet clear of the rungs, he plunged back toward the deck,
guided only by his hands brushing the sides of the ladder. As Phillips
reached the junction of the passages, he kicked desperately away from
the ladder. He landed with a thump that would have hurt had he been in a
calmer state.

Rolling over toward the control room, he came to his feet in time to
glimpse Donna looking out the doorway before a jarring shock floored him
again.

The deafening roar of an explosion resounded in the corridor as a
brilliant light was luridly reflected from somewhere behind him. The
bewildering force hurled him at the deck; he saw he could not prevent
his head from striking--

Phillips found himself on hands and knees, staring stupidly at the deck
a few inches past his nose. As in a nightmare, he seemed to spend an
eternity pushing himself painfully to his feet. Clutching a handrail, he
finally made it.

He saw Donna kneeling in the doorway, hand to head. As he watched, the
girl looked at her hand, and dazedly pulled out a handkerchief to wipe
off the blood.

Then Phillips became aware of a high breeze in his face. Behind him, the
sound of rushing air rose to a moan, then to a shriek. That shocked him
to his senses.

"_Button up!_" he screamed above the n