Paperwork, civil suits, internal affairs; small town, and he may have thought the guy wouldn’t really pull the trigger on him (history has shown that that was probably a false assumption if it is one that he made).
I do wonder if the guy had a history of being a mean snake, or if he was evidencing age related personality changes.
I doubt that he was thinking about all of that at the time he just didn’t want to kill anyone. I’m sure he did make a judgment that the guy wasn’t going to shoot though. We have some pretty good LEOs in CO.