BEVERLY HILLS, CA - MARCH 21: Comedian Ellen DeGeneres attends the 26th Annual GLAAD Media Awards at The Beverly Hilton Hotel on March 21, 2015 in Beverly Hills, California. (Photo by Jason Kempin/Getty Images)

Ellen sat down with Mandalay Bay security officer Jesus Campos and building engineer Stephen Schuck, who were the first people to encounter the assailant on the night of the mass shooting.

Watch the interview below: