> Was he even aware of the potential lethality?

It could be worse than that. He might not have even known the actual purpose and complete function of the system for which he was writing code.

That's common when big projects get outsourced. One might call it "decomposing the problem into small tasks" but it ends up with people writing code for machinery that they have no knowledge of. I've seen this myself. These kinds of projects depend upon layers and layers of oversight and process.

I think that the folks who are looking for "a perpetrator" are utterly missing the key-value of studying the Therac-25 case study.

I am personally not looking for "a perpetrator". Many people share responsibility for a failure like this. But that's all the more reason that we should clearly describe who did what, when, and why.

Please note that you are working very hard to make up a fantasy situation that entirely exonerates the person like you. Your fantasy does not match the known facts. Think hard about why you think that's the most important thing for you to do here.

He knew or should have known the potential consequences of the code he was writing. Maybe this could have been you, but it definitely wouldn't have been me, because I would not have committed the first line of code until I was reasonably sure that a) I was not going to kill somebody accidentally, and b) the project had sufficient safeguards.

I'd also like you to note that you're pointing out the lack of accountability as a problem, and then dismissing one of the fundamental mechanisms of accountability: naming people who harm others.

Yes, other people on the project also should have pushed for traceability and accountability. But responsibility is not zero sum. "I was just following orders" is never an excuse for killing people.