It was the door to a small airlock. Dark led Maya through it into a huge room.
A helicopter stood in its center.
"Goat did leave it here!" exclaimed Dark joyfully. "I'd forgotten that he had this. He must have just packed the most necessary things when he left the place, planning to send trucks and a crew back and clean it out later at his leisure. Now, if this copter's only in good flying shape, we're set."
He checked the machine over. Everything was in order.
"How do we get it out of here?" asked Maya curiously, looking around the room. "That little airlock's too small for a copter to go through it."
"The roof rolls back," said Dark. "Put on your helmet, and I'll show you."
Maya donned her marshelmet. Dark went to the wall and pulled a switch. Nothing happened.
"I forgot," he said. "The electricity's off. Well, let's try something."
Dark concentrated his mind intensely on the movable ceiling. For a moment, there was resistance, then, very slowly, it began to open. A crack appeared in its center, and the air of the room hissed out with the swish of a minor tempest. After that, it was easier. The crack widened swiftly, and the roof rolled back to the walls, leaving the room open to the heavens.
"All we have to do now is to climb into it and go," said Dark with satisfaction. "You fill the fuel tanks, and I'll run down to the motor pool and pick up those other two marsuits. One of them is for my friend Happy, who is very fat, and he couldn't wear either of the emergency suits in the copter."