I disagree - U have no idea of knowing os what state he really was in. There are a lot of people who do get suicidal - most that get to that level have severe pysch problems. I have had probationers with psych problems flip out and try to kill others and then themselves.
Sometimes, the public will criticize police action and say "he only had a knife." A knife wound can do more damage than a bullet, depending on where U are cut. U do not want to get into a tussle w/ a guy w/ a kife unless U have no choice and are fighting for your life.