There might be "plenty of castle doctrine cases" in other states that would support the "life needs to be physically threatened" idea, but not in Colorado. At least, not since 1985 when the "make my day" law was passed.

Colorado's statute is somewhat unique among castle doctrine laws. In (many? most?) other states, it's true that you need to be in fear of death or great bodily injury. Colorado's law goes much further - saying that you only need to have a reasonable belief that the intruder MIGHT USE ANY PHYSICAL FORCE, NO MATTER HOW SLIGHT. By using those exact words, our legislature expressly lowered the bar to a point way below the level of "your life needs to be physically threatened".

If you disagree (and have the time to support a position that clearly differs from Colorado statute), please cite any case in Colorado where the defendant met all of the conditions of CRS 18-1-704.5 but was convicted solely because his life wasn't physically threatened.