that were there there. reporter: ambulances blocks away from the safety perimeter. i remember, use my truck. get them ouch heout of here. another officer jumped in my truck, take them from behind the cars and load them on the back of the truck and take them down to the hospital down the street. reporter: 15 trips in all as frantic phone calls come steadily from inside the night p cl nightcl nightclub. advising reloading in the bathroom. reporter: 30 minutes into the attack, the self-proclaimed isis gunman exchanges three phone calls with police. you have some vehicles outside that have some bombs, just to let you know. your people are going to get it. i m going to ignite it if they try to do anything stupid. reporter: a new threat as a bomb dog identifies the scent of explosives in the gunman s car. dozens of police and deputies work quickly to rescue survivors hiding throughout the club. some two dozen hostages remain