He was outplayed by those 3.

For convenience here is what he said happened further down in the comments.

I don't have replay but it was close to the end of battle on Abbey, I came back to base to defend against two T54E1s and hid behind one of those rock things so I wouldn't get fucked by artillery. One of the T54E1s was left alone and when I took him down to something like 300HP I decided to rush him and this happened seconds afterwards. But why am I even serious, this is meant to be a shitpost (seriously balance arty).

I'll assume everything he said is 100% factual.

A 300-something health T54E1 dies in 2 shots occasionally from a 7/1's 390 alpha thanks to the +/- 20% damage per shot landing it a minimum damage of 293. With an aim time of 2.2 seconds he is relatively likely to take 2 shots from the T54E1 unless he is willing to gamble on the shot accuracy (dropping his chances of killing the E1 even further). The T-34-85 (that actually received the kill credit) will hit for 180 health and will get a second shot if OP goes for the E1. So if he plays it safe he has lost 3902 + 1402 = 1060 health on average. The arty should hit him however when he is leaving this cover while spotted (arty likely has nothing better to aim at at this stage of the game) With his armor any direct hit from arty either hits his front plate, front turret, tracks, or fully penetrates. Assuming this masterful arty manages to hit OP's front plate in a way that he would benefit most from arty deals (1890/2) - 120=825 damage. The three tanks combined have a decent chance of doing 1060+825=1885 damage. OP rolled the dice. OP lost. Op is overly salty.

This is before we consider that one troll bounce or "lol RNG" miss leaves him eating 1550 damage from the T54E1 and 280 from the T-34-85 and has him dead anyway.