Hardcore instant death - Barry was slain by Barry

My barbar was instantly killed in NM dungeon same level as him approx. Level 89 mobs and he was 87-88.

Had potion and it seems the instant I klicked mouse to do ww I died.

then it said:

Barry was slain by Barry

It seems that the potion did not proc. I have played several other toons - also a mage to 100 still alive. Killed duriel etc. Also died on lillith on another toon. Soo have played a bit HC…

This (the fight and the mobs) did not feel anything dangerous , I didnt loose any HP, just instantly died. I dont think death potion either got used?!
I had scroll ready to be used and used potion soo I should have the 2 seconds from the potion. This seems very strange to me…
Anyone know why its says Barry killed Barry?

Regards,
GD

PS, I was testing the 46k damage ring (lucky hit ) from duriel (i think duriel) maybe it set of 2 times very fast?

Its on the European server.