Nightclub Fire Kills 231 in Santa Maria, Brazil tonight, we are learning more about that staggering loss of life during the fire in a nightclub in brazil. 231 people killed, no alarms, no sprinklers, no fire escapes. And tonight, american experts are studying this tragedy for the lessons that could save lives here at home. Abc's matt gutman is in brazil at the scene for us tonight. Matt? Reporter: Thank you, diane. This is the nightclub and those are the doors through which nearly 2,000 college students tried to squeeze through at that fire raged, as you also see here where good samaritans and firefighters used sledge hammers to break through into the bathroom and try to drag people out here to safety. But the pain here is still very raw tonight. Families shattered by tragedy, holding onto these coffins and those photos. All that's left tonight of loved ones. This, as tonight, arrests are being made. The club had no alarms, no sprinklers and no fire escapes. It was just after 2:00 a.M. Sunday when this photo posted on twitter alleges to show the moment the band on stage fired pyrotechnics, quickly igniting the ceiling over some 2,000 club goers. Flames and smoke spread fast. College students panicked, rushing to the only exit. Witnesses say at first, security guards stopped people from leaving, thinking they hadn't paid their bills. In that dark chaos, hundreds crushed against the exit, dropping from smoke inhalation, their bodies blocking the door. Hundreds would die trapped. Others used the bathrooms for exits. In 2003, it was the nightclub fire in rhode island, 100 dead, 40 jammed and killed at one door, when there were three other exits. You only have seconds for you to react and make a decision as what you're going to do. Reporter: Safety experts say whether you're headed to a movie theater, a restaurant, any place unfamiliar, there are lessons. First, look around. Not just at how you came in, but at all the exits and how to reach them. Research shows us that in the chaos, 80% of us will simply go with the flow. Breaking from the crowd and reaching one of those other exits could save your life. If there is a fire, keep your body low. Temperatures near the floor could be 1,000 degrees cooler, buying you time. Diane, the air here still heavy with that smoke and all day, people have been leaving flowers and bouquets and standing over here, the mourning here has just begun in this town.