There were just days left to process a batch of federal financial aid applications when Education Department officials made a fateful discovery: 70,000 emails from students all over the country, containing reams of essential data. They were sitting in an inbox, untouched. That discovery last week started a panicked, three-day crash effort by more than 200 of the department’s employees, including Richard Cordray, the nation’s top student aid official, to read through each of the emails one by one and extract crucial identifying information required for financial aid. The students’ futures depended on it.