Myrofibrils increase melee damage by 60% each

A multi-punch glitch allows you to fire 3 punches or so within a second.
Myos boost attack to 400..... hits x 3 = 1200 etc.

Either punching is going to have an enforced cooldown soon, or the damage mods are going to get a huge slap.
Nova Knives should be the default close combat, while melee should be a cleanup, if a small portion is left.

Pretty sure it shows you how much damage did the person who killed you dealt over your lifespan.

That's incredibly rude.

Amarr Assault with x3 Complex Myros does [563.76] damage per melee, which you said he hit you twice which means he did [1127.52].

As others have mentioned, it accumulates the damage that person did over your life-time, so it is very very very possible he had shot you previously and you recovered from it and you either failed to mention that fact or simply forgot.

Or you just got duped by one of the many glitches in Dust. Considering I've seen basic locus grenades do over 800 damage, it wouldn't surprise me if the game registered the damage wrong. I doubt there's a glitch that multiplies the damage to levels like that though... although... any commando at this point with three Myofibrils on can dish out 1230 damage per swing.

If he did some damage to you earlier and you repaired it, it's added on to the damage total shown in the death screen.

every time someone dies to melee I cry a little (tears of joy) then i think to myself

self awareness OP, seriously look around notice your surrounding and don't let any enemies get close to you, KN's can do just as much damage and have better range

It was a plasma splash and 3 punches jordy, it's hard for some to take in what hit them in the heat of battle. Consider the classic fog of war ( Lag delay + unnecessary atmospheric fx) and some deaths may be confusing.