"There was a loud sound and everyone started screaming and running," said one student, who hid on the floor of her math class when the shooting broke out.
The alleged gunman, who is a student at Great Mills High School, was fatally shot by a school resource officer on campus after he shot two students.
"It's the craziest thing. It could have been very bad."
Police named the victim as 39-year-old Dannta Holmes.
The observation reports span six days, beginning three days after the February 14 school attack.
The shooting panicked students and faculty at Central Michigan University, which was on lockdown most of Friday.
One of the men emptied a revolver but for one bullet then spun the chamber and aimed it at his head.
The latest in a long, long list of American mass shootings, and school shootings in particular, has provoked an increasingly familiar reaction. Hugely emotive, of course, the survivors, and families of the dead have, by and large, questioned the U.S. addiction to guns. The political response, tweeked by the puppet strings of the gun lobbyists, has been to offer "thoughts and prayers," the mealy-mouthed response of those who intend to do absolutely nothing in response to yet another tragedy.
The military has moved quickly to add a backlog of thousands of names to the list after the mass shooting by an ex-serviceman.
The unnamed teenager died in the early hours of New Year's Day.
"We find ourselves in a more dangerous situation," an outgoing counter-terror chief said.
Police have arrested a man suspected of nine random killings and more shootings after a year-long chase.
More than 200,000 people are serving some form of life sentence in the U.S.
Republican Joe Walsh appeared to forewarn the president.
One of the victims in the massacre was a 38-year-old mother of five.
More than 40 of the top 50 cities are in Latin America, with four in the U.S.