Simply showing up isn't enough.
"You want to have an entrance plan but also a completion plan. Can you make it out? Can you make it to safety?" he asked rhetorically.
Officials at the Moore School District choose not to dismiss students early. But that, too, is a tough call.
Troy Albert, a principal at Henryville Junior-Senior High in southeastern Indiana, let students out for the day on March 2, 2012, just moments before tornado sirens went off. No injuries were reported among the few staff, students and parents who remained at the school when a tornado packing 175 mph winds destroyed the building. School officials halted people from leaving only when they figured the tornado was within 10 minutes of hitting, fearing that wouldn't allow enough time for people to make it to safety.
"We trusted our protocols and it worked," Albert said. "I was questioned about whether we should dismiss school or whether we should bunker down here. Our decision to do that was based on the fact of the size of the tornado and what was coming. And we figured if you got them a mile away from our school you had a chance for survival."
With about 30-45 minutes of lead time on a potential tornado last year, Julie Hubbard jumped in her car and signed her son out of a Tennessee middle school ahead of the storm.
"There were just dozens of parents who went to pick up their kids that day. I don't know if they just tended to freak out more or what," said Hubbard, who now lives in Fort Gibson, Okla. "Growing up in Oklahoma, we have so many tornadoes. I just wanted to be home with my children."
A couple of hours before deciding to pick up her children before the tornado barreled through Moore on Monday, Sharp said she called the school office at Plaza Towers Elementary and asked if it was safe for them there. She said the receptionist replied: "They're pretty safe here."