The easiest way to avoid regrets is to ask yourself this question, "If not now, when?" It's a powerful way to put life and our decisions about how we spend our time into perspective"
There's no way for you to know this, of course, but I'm wondering if the sales lady might be diabetic and was having low/high blood sugar issues.
When you write your follow-up email, I might include that I now regret not calling 911 because it now seems the sales lady might have been having a medical emergency.