dr. leona di amore was visiting her daughter on campus when she heard screams and saw people running.e's a former navy medic who now works as a chiropractor and instead of following the crowd, she ran toward the danger and immediately started treating a badly injured student. >> i did run, and when you're military trained and you're a first responder, and things are going down, that means they need help. i was meant to be there for him that day. there's no doubt in my mind. >> now, one student was killed in that incident. the young man di amore helped and two others did survive the attack. she believes he would have died within minutes if she hadn't intervened. >>> and a new study shows a possible correlation between screen time and speech development. researchers in canada followed more than 1,000 children under age 2 and found the more time they spent playing with smartphones and tablets, the more likely they would be to have delayed speech. the study says even kids with just 28 minutes of screen time per day showed significant delays. >>> up next in "the pulse," stephen colbert res