donna friezen covers the story as a correspondent for nbc news. >> these weren't suicide bombers. backpacks placed in the trains by terrorists who placed them then got off the train and left them. there were roughly 20 pounds of explosives in each backpack. and also filled with nails and screws and various shrapnel so there would be maximum damage. and they were all detonated by cell phones. so they had cell phones in them that the perpetrators then dialed the numbers of the cell phones. >> viamoran is standing in the same train car that is carrying one of the backpacks. shortly after the explosion knocks him unconscious, he begins to regain his senses. >> translator: i started to feel the pain of not being able to move. i was paralyzed. my body was almost totally burned. i can only move my right arm. i was feeling the pain of not being able to breathe because my lungs had collapsed. my face had also been burned. and amid other people's blood, my own blood, the skin that fell on top of my eyes, i saw everything in shades of black or red. i had no sensation of time. i just know tha