How do I prevent my watch from listening to my conversation and calling 911?

I was talking to a friend, telling them a story I had heard about a person that jumped off the Aurora Bridge in Seattle, and lived. During the conversation I said the word "suicide" a bunch of times. The next thing I know, I hear Siri announcing that she is calling emergency services, and before I know it she has dialed 911. I was not aware that I should not immediately hang up, so this was followed by a number of different emergency services calling me up to confirm that I was safe and everything was okay. To my surprise, none of them found anything particularly unusual about what had happened.

Anyway, I am sure that I did not press any buttons on my watch during this conversation. My assumption is that the watch keyed off of the word "suicide" being said so much in phrases like, "jump off the bridge, trying to commit suicide", and the AI decided to call for help. I can't find a setting that would stop this from happening in the future.

Does anyone know how I disable this function?