Hot Ice

"We weren't born in a Vault," Vanessa began. "In fact, we didn't live in a Vault until I was six. Four years ago. We never knew our parents. Well, at least, we didn't know that Dr. Sumart was really our dad until a year after he was dead."
"That sucked big time," Melissa added.
"Anyways, we weren't on our own. Mrs. Amy took care of us. She was so nice. She had a dog called Venus, and when Venus had puppies, she gave one to us. We wanted to call Fire Jupiter at first. We tried to train him to come to his name, but he just wouldn't respond.
"So one day, after two months of unsuccessful training, some lightning lit a brush fire. That happened all of the time, you know, but it just so happened that it was only about a hundred yards away from where Fire was sleeping. The dog can sleep through anything- a hurricane, people screaming as a meteor streaked toward them, seagulls, absolute quiet- as soon as he hit the ground, he was out. So we ran toward him, screaming 'Jupiter, Jupiter!' and he just lays there. Then I scream, "Jupiter, there's a FIRE!"
"And then I say, 'Fire! Fire!' and he comes running. We don't know why he responds to Fire, but he does. Later we changed it to Firecracker, after he ran toward a firecracker spitting sparks and caught his tail on fire." Satisfied, Melissa finished the story.
"That's cool," I said, reaching over to stroke Fire's ears. "But how did you get him into a Vault?"
"Well, the Vault didn't have an Overseer," Vanessa explained.
"What?" I couldn't believe my ears. "I thought that a Vault had to have an Overseer. Who was in charge?"
"No one. We all helped each other. We all shared two ovens, and eight tables, and pots and pans. Mrs. Amy always said, 'Why do eight women need eight stoves?' There weren't many people living there, anyways."
My brain spun. A dog that responded to something he'd never heard before? A Vault without and Overseer? What was next?