Sam, sorry, I missed your response before.
As DY notes, that is obviously not the halacha since everything in the world has some safek of causing death–and in fact most everyday things have a much higher risk than does MBP. And more on point, bris milah itself can cause death in some situations and we only don’t do it when there is chazaka from the brothers that (I think) 3 already died from bris.