Work long enough and a person will screw up. That's how things go. And if you never screw up, then you're not really pushing yourself. Personally, I've deleted customer tables, updated the whole table when meaning to update one record, even shipped our private key once. There are probably even more I can't remember, and others from people that I helped fix (one time a boss locked us all out of the db - only fix was restoring lol) In all cases I became a better engineer by owning the mistake quickly, fixing the issue, and then putting processes in place to avoid it in the future. I think it shaped who I was to be a better engineer, manager, and owner.

The only time I've seen people fired on the spot is when they lie. After seeing someone fired, I asked one of the owners at an old company I worked at why that was the line. He responded that even the best performers make mistakes, but if he couldn't trust someone, he couldn't work with them. This was many years ago, and as I've grown in my career I have found it to be a pretty good line to draw.