Round nose slugs not only deflect, they occasionally push blood vessels out of the way. Quite awhile back, a gent in my apartment complex got shot in the mouth with .45 hardball during a gun cleaning party. The round entered the mouth (lost at least one tooth), grooved the tongue and exited through the neck without serious damage. Major blood vessels were gently pushed to the side.

I used to have a newspaper clipping on an incident where a cop shot a knife wielding teen in the forearm to disarm him. Slug deflected off the forearm bones, the upper arm bone, hung a hard left and traversed the chest cavity from left to right, cutting the blood vessels over the heart in the process, and lodged in the right bicep.