To make comparisons, IIRC the failure ratio of the unmanned missions is 10-15% and in the manned missions is about 2%.
An important detail is what happens when 3 or more engines fail simultaneously. Can they transform the mission in a soft landing or the "payload" is totally doomed? (For example, the Apollo XIII mission was a failure, but no one died.)
For a crew mission, yes the mission would be aborted and the Dragon launch abort thrusters would fire getting them away from the rocket as fast as possible and deploy a parachute where they would land in the ocean.
An important detail is what happens when 3 or more engines fail simultaneously. Can they transform the mission in a soft landing or the "payload" is totally doomed? (For example, the Apollo XIII mission was a failure, but no one died.)