Originally Published: 06 JUL 22 20:49 ET

Updated: 06 JUL 22 22:33 ET

By Shimon Prokupecz and Matthew J. Friedman, CNN

(CNN) -- As he lay in his own blood, with dead and dying students around him, Arnie Reyes knew help was just outside the classroom door.

Twice he heard law enforcement officers in the hallway of Robb Elementary in Uvalde, Texas, call out to the gunman who was in the room with him. And twice they went away.

"I was thinking, you know, come on, come in, come in. Like he's in here. Just come in here, come save us," he told CNN.

"And they weren't. I didn't find that out until after the fact when I saw other videos where they're standing in the hallways and that even makes me more upset, just knowing you're a few feet away from me and you're not helping me. You're not helping anybody."

Lying there, for over an hour, doubting that he would survive, Reyes said he could only think one thing of those sent to help: "That they forgot us. They saved everybody else except us. I mean, they probably thought that we were all dead or something, but if they would have gone in before, some of 'em probably would have made it."

The response to the shooting has been largely condemned. While officers from multiple agencies, including school and city police, state and federal law enforcement, soon arrived on the scene with weapons and safety equipment, no attempt was made to engage the gunman for more than an hour. Official accounts of what happened that day have also changed significantly and the local mayor told CNN he fears the truth may never come out.

Reyes has already made up his mind about the massacre that killed 19 children and two adults.

"A lot of the law enforcement failed, cos they take that oath to protect," he said.

"Everybody needs to get their fair share of the blame because they all did just stand there."

Shooting in silence

Reyes initially discounted the noise of the attack on May 24 as just someone hitting something hard.

But as the shots came closer and students started asking about what they were, he became concerned.

When the Sheetrock began flying off the wall from the bullets being fired from the high-powered rifle in the next-door classroom, he told all the students to get under their desks and pretend to be asleep.

"And then it dawned on me that it was a gun, it was a gun," he said in an interview. "I just felt like all the badness that was gonna happen ... was gonna happen."

Even before the gunman came to his room, and came through a door where Reyes had repeatedly reported a broken lock, the teacher did not think he would live through that day. And all around him was quiet.

"When the gunshots were going on, no crying, no nothing. It was just complete silence," he said. "And so I thought, well, he had hurt everybody on that other side. And then he came to our side and did that to us."

Reyes remembers seeing two flashes come from the gun as he was hit. Then he thinks the children were shot.

And then there was the waiting.

The gunman stayed in the room with Reyes. The teacher said his breathing was so shallow he may have appeared dead but it seemed the killer wanted to check.

"He did a lot of things to make me flinch or react in some way," he said, remembering how blood was splashed on his face by the attacker tapping or splashing on the floor near him.

He was shot again, in his back, as he lay on the ground, and still he had to play dead.

Finally, after 74 minutes, the door opened, and the gunman was challenged and killed.

"After they shot him, the Border Patrol said, 'Anybody get up, let's go, let's go,' try to get the kids out," Reyes said, his voice shaking at the memory.

"Nobody moved but me."

His funny, ambitious students

A total of 19 nine-, 10- and 11-year-old children and two teachers were killed that day.

Hours earlier, Reyes had been celebrating Awards Day with his students, and then putting on a movie in Classroom 111 for those children who stayed after the ceremony to chill with friends. Eleven students were with Reyes when the attack began. None survived.

Reyes, who was shot in the arm and back, spent 31 days in the hospital and has undergone 10 surgeries so far.

He said he first felt guilty that he had survived, but now embraces the love and concern of community members who told him there is a reason for him to be here.

"That's why I'm being as strong as I can, because ... I would not let them die in vain. I would try to do anything that I can, so we don't forget them," he said of the massacred students.

He said he tries not to think too much about the students though he will often find himself reminded of one or other of the youngsters he calls "my children."

And talking about them helps, he said.

"They were good kids, funny. A lot of them were ambitious," he said.

"I had all kinds of kids in there, so, you know, from one extreme to the other, it was just like, oh my God. But they all got along together so great. They just, they had a bond, they had a real bond," he added.

Reyes, the proud teacher, wiped his eyes. "I love those kids."