He turned it on again when they reached the opening in the metal wall. "Well?"
"I've been trying to get you," Rodney said, frantically. "Why didn't you answer?"
"We couldn't do anything for him."
Rodney's face was white and drawn. "But he did this for us."
"So he did," Martin said, very quietly.
Rodney said nothing.
Then Martin said, "Did you listen until the end?"
Rodney nodded, jerkily. "He pulled three more switches. I couldn't understand it all. But—Martin, dying alone like that in a place like this—!"
Martin crawled into the circular pipe behind the grate. It tilted up toward the surface. "Come on, Rodney. Last lap."
An hour later they surfaced about two hundred yards away from the edge of the city. Behind them the black pile rose, the dome of force shimmering, almost invisible, about it.