During engagements online, it is very clear that not all instances of the player taking damage are conveyed to the player (such as a vibration, screen flash or audio cue).
This can make the player feel he “died one shot too early”.
Examples are more obvious in the precision weapons that it is perceived that you die in only 2 or 3 hits when in reality the opposing player hit you with 4 or 5.
Further discussion via my Reddit thread. http://www.reddit.com/r/halo/comments/2rmw85/halo_5_beta_i_feel_like_i_die_one_shot_too_early/
Still enjoying the heck out of the beta! I want to help it be less frustrating for players upon death.