You paint with a very broad brush.

He was paid to protect the children and staff at the school. He accepted the job, the pay, and he decided to disregard his duty.

I agree, but the state wanted to send him to prison for life. Too much of a penalty.

Agreed completely. I am in favor of stricter gun control (not eliminating guns - just controlling access more efficiently). I am against excessive force or choke holds for criminals by police officers. I am often accused of being a bleeding heart you know what.

But I'm not really. I'm just practical and pragmatic. What will actually WORK to help the MOST people, as a collective group and not any specific demographic, with the least possible damage or expense to anyone else.

I hate that this cop didn't go in and shoot the shooter. However - the pragmatic me realizes he wouldn't have lived to tell about it if he'd tried. And I think he knew that. He needed to do SOMETHING though - and he failed, until it was too late. For that, he needed to be stripped of his job, his weapons, his responsibility, banned from serving the public as an armed -anything- ever again, anywhere in the USA. Possibly fined, but probably not even that. AND he should be subjected to civil lawsuits from the families of the victims.

Parkland school shooting families settle suit with district

That seems to be happening. The lawsuits against the school resource officer.

Scot Peterson: Then-Parkland school resource officer found not guilty | CNN

I do not know the specifics of the incident where he might have acted and had not. He may have been telling the truth when he said he did not know where the shooting was, how many perps and what kind of armament he/they possessed. I am not saying that he acted prudently, but I am not saying he did either. I know of several incidents where a veteran officer was attempting an apprehension and a rookie officer stood back, confused as to what to do. Was that officer acting cowardly? Or, was it just his/her lack of experience? I do not want to see officers of the law punished criminally for failing to do something when there is also the possibility of them being charged with excessive force, just because the perp is black or female, etc. I have seen many/many choke holds that worked to subdue the perp, and NONE of them resulted in a fatality. Yet, in the past few years it is suddenly a bad act when the dirt bag criminal with a violent past perishes due to excessive force. It seems like every time a choke hold is used with fatal results, the subject has a repeated criminal record of violence and drug usage. But, I digress.
From the little that I know of this situation, I would NOT agree with the officer being charged criminally, but with the little that I know I would probably wish to see his employment terminated. But, like I said before I know little of the details but a lot of opinions on how everyone seems to think happened.
I have a former police officer friend that has been in shoot or don't shoot situations where he would have been justified in killing the subject, yet he held back and the situation worked out favorably. He was NEVER, EVER accused of being a coward. Although, no one was injured seriously in those incidents. Some of us are fast to judge folks for not reacting fast enough in these situations. It's easy to criticize later. Law enforcement have to make critical decisions in seconds and they must have all the facts to act appropriately. Making a life depending decision in a split second is usually based on a "gut feeling" not always based on available information. I believe this officer was working by himself, without anyone backing him, watching his back and giving him support. Maybe he made a bad decision, or maybe he was waiting for support. If he had rushed in and resulted in making things worse, he would have been accused of being brash, careless or foolish. The results determine the hero from the fool.