6 feet and 15 minutes are not concrete numbers on contracting a virus. The more people you come into contact with increases the odds of transmission. It's how superspreading occurs.
That is what I've said, but I was told by several in other threads that I should not worry about those other shoppers in Target because I was by them for at least 15 minutes, and this was not from the anti-mask people, quite the opposite. It seems to change on a regular basis what some people say is correct and what isn't. I haven't gotten that from you, but a handful of other posters.