Finally he moved Exman to the bottom of the steps and signaled simply: Go up!
Exman paused for a moment, then attempted the ascent. His caterpillar tracks clawed their way up the first step. Then, gingerly, he essayed the next.
The robot body tilted, but its gyro kept it from toppling over.
“Bravo!” Mr. Swift applauded encouragingly. But the next instant Exman gave up! He slid back to the floor again with a heavy bump. Then he began whirling and darting about madly.
“Good night! Exman’s gone berserk!” Tom cried.
Now wafts of smoke could be seen issuing from the robot’s wheels. He was banging wildly about the laboratory, leaving a trail of havoc.
Bud, who had returned, opened the door to come in. Instantly Exman lunged toward him, antennas sparking fiercely and wheels smoking. Bud slammed the door hastily.
The Swifts, too, found it wiser to take cover. They crouched behind a lab workbench until the frenzy was over. Presently Exman subsided and rolled to a complete standstill.
“Good grief I” Tom stood up cautiously and
DISASTER STRIKES 111
eyed the creature. It made no further move. Bud poked his head through the doorway for a wary look, then re-entered the laboratory.
“What made him blow his top?” Bud asked.
Then Tom heard a quiet chuckle from his father. “Actually, boys,” the elder scientist said, “I think we should be encouraged.”
“Encouraged?” Tom stared at his father.
Mr. Swift nodded. “Yes, the whole thing was rather a noteworthy reaction. I believe Exman was displaying a fear complex about navigating up those stairs.”