. >> reporter: san bernardino police officer sean sandoval was in the first team to go in. his instructions, find the shooter. meaning, he could not stop to help the wounded. and the looks on the victims' faces. you can't describe. knowing that some were alive when you entered -- and when you came back they were no longer living. left a huge burden, almost a burden of guilt that we didn't help them and they didn't survive. >> clearly it still bothers you a year later. >> there's not one day that goes by that i don't think about it. >> reporter: but right behind where other officers that could including county probation officer nate scirano. >> when i encountered that first group of people it sucked the air out of my body. with all the noise including the fire alarm going off, i heard a faint voice. "help me, i'm going to die." that was the second time i lost my air. i couldn't breathe. i looked down. next to my leg, in front of the severely wounded. >> i was begging. please help me, please help me. >> she proceeds to tell me she had been shot. very nonchalant, very catatoni