Pretty much everything in development relies on the work of other people. I used 3rd party lib just as an example, but what if it's in the framework or even the language that an engineer uses, who would be at fault then? You can't expect every developer to have gone through the entire source code for whatever language they are writing in.

Sciences build on each other and and after a certain period of time you have to take things for granted in order to keep moving forward.

> The same rules apply for medical and other areas.

No, they don't. Doctors kill patients all the time and they aren't banned from medicine for it. There is an investigation, they make sure it wasn't intentional and there wasn't any gross negligence and that this isn't a repeating pattern, if none of those are the case they see what they can learn from it and move forward in hopes that what they learn can help other doctors.