[Glitch] 9 AR Rounds + 1 BR Shot = Perfect Kill?

I couldn’t replicate this in custom games. It happened in Matchmaking though. Can’t understand why it happened, but seems to be a once in a lifetime event.

Literally, 9 AR rounds into a guy, and followed up with a final BR shot. I cant wrap my head around what circumstances would cause this to happen, yet I’ve seen no mention of it ever happening anywhere else.

AR+Perfect Glitched Perfect Kill

Thoughts?