My last post on this thread:
I know about the dot of incendiary ammo that let you even without shotgun medals or any other weapon medal, the thing is, in those +75 shotgun kills you didn't get the headshot medal, even the worse player using reegar + Krogan get the headshot medal because at some moment of the game if you are soloing ( mainly platinum ) you will get enemies very close, and faster units like Draagons, Hunters and Phantoms are never alone, so if one of those get very close to you is more likely that you will shot the head since from the Krolord perspective it is much easier to aim to the head because otherwise you have to look down too much due to the size of the warlord.
Besides, as I told you, faster units like Draagons, Hunters and Phantoms are never alone, they move in little groups, which means you won't have time to shot at them and let them die with the DoT, you have to kill them as fast as you can, otherwise you will be dead very, very fast. So the DoT stuff doesn't fit here.
About the melee, even if you use it very ocasional it is weird that you don't use the Biotic Hammer, which also give you melee kills, that's how I know that you didn't use it enough and also, Biotic Hammer detonate fire explosions of your reegar, amazing for bosses with ARMOR and even better for a small crowd control, you could kill enemies nearby bosses with the fire explosions and it would give you tech kills, but you didn't do that, you didn't got tech kills either and that means that you were completely relying on your reegar.
And I know that even reegar being so powerful, is not powerful enough to keep you alive on a plat solo without detonate any combos ( because you were not using the hammer ), because you were not with rage and its damage reduction activated most of the times, otherwise you would have melee kills.
So you were also without that health regen speed, and the health regen speed without rage is nothing special to keep you alive in platinum.
So, I know that it would have take you more time on Giant to do that solo only using Reegar, that's why I say you used a trainer, because you didn't even rely on fire explosions to stay away from sync killers, but you also didn't spend too much time running away from them because the map is big and the time is fast. So I think you used one of those cheats you know, one of those cheats that give you 1 shot, 1 kill or maybe a modification to the coalesced but I say is not legit.
The funny thing is, the players with good knowledge about this game are agree with what I just said

, we are not stupid.