"You just never imagine that you're going to walk out of your classroom and there's going to be nothing there," Bittle said.
Lowe said that she has not been so sleep yet because, "Every time I close my eyes, that's what I see. And it's very scary."
Both teachers rebuffed the term "hero" when asked about the praise they were receiving.
"It wasn't heroism, it was survival," Lowe said. "I just wanted to keep them all safe. It was my responsibility when they're in my classroom and that's where we were."
"Your child is my child. All day long and all year long, from August to May," Bittle said. "And I will do anything to take care of them."
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"Safety is our main priority and the decisions we make are always with safety in mind," Susan Pierce, superintendent of Moore Schools, said at a news conference today. "We are in the process of learning as much as we can about what has happened and we are reviewing our emergency procedures today."
The two schools were not funded for safe rooms, according to state Director of Emergency Management Albert Ashwood.
"You have a limited amount of funds that are based on disasters you've had in the past that are used for mitigation measures and when you have limited number of funds, you set priorities for what schools you do want to ask for," Ashwood said at the news conference.
He said Briarwood and Plaza Towers were not being left out, but, rather, had not been brought forward yet for safe rooms.
"We're going to be looking to try and up that number and try and get more safe rooms in schools across the state, the entire state," Ashwood said.
One sixth-grade boy from Briarwood named Brady said he and other students took cover in a bathroom.
"I was in my classroom building and we were told to get in our tornado precaution system. Then they moved us to the boys and girls bathroom," he said.
"Cinderblocks and everything collapsed on them but they were underneath so that kind of saved them a little bit, but I mean they were trapped in there."
Josiah Parker, 8, escaped Briarwood unharmed but couldn't find his parents in the immediate aftermath of the tornado.
"If our school is crushed, my house is like directly behind the pond and so I think it might be crushed, too. If my mom and dad are still alive, they're probably going to take us to a hotel," Josiah said.
Josiah's parents survived and the family was able to reunite.
Students remained at Briarwood despite the tornado warnings because there were safe areas they could be protected.
Moore resident Andrew Wheeler credits a Briarwood teacher with keeping his son safe as the tornado wrecked havoc on the building.
"The teacher held their heads, and bricks and everything were falling all over the kids," he said. "She got her arm injured. One of the other boys on her other side got a big gash in his head, but he's OK."
Wheeler's son, Gabriel, says his teacher stood with the class the entire time and told them to act as they did in practice drills.
"The roof came off and then I felt something and it was just raining clay on me and all that," Gabriel said.
This twister was the latest in a group of violent storms that swept through the Midwest, starting Sunday, that has now left dozens of people dead.
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ABC News' Lauren Effron, Dean Schabner, David Muir and Ginger Zee contributed to this story, which was supplemented with Associated Press reports.