OCG needs 16 ocrruptions, not 15, doesn't it? Shredded with speed 1225, BoW, MWM,etc

Trying for my first OCG ending. Had the trinity, was crowned champion of chaos, was not intrinsically doomed, was corrupted to O. Entered chaos gate, successfully passed a mass of writhing tentacles and a huge chaos night, but was torn to shreds by multi-tentacled horrors of unspeakable might (saying "not one of us").
Did I need to be corrupted to P?

...man, my speed was boosted to 1225 and I had missile weapon master, bracers of war, boots of the far wanderer, nature's companion, helm of the night watchman...I'm pretty sure I was going to slay Mr Drakon.

You need up to Q. That's the point where the game says "You feel extremely corrupted."

Ah, that seems more obvious, then. I haven't actually been extremely corrupted since maybe 2003, between large gaps in playing, toned-down background corruption, and often playing L+. Remembering that message will make it easy to not slay myself again.....in this particular way. Thanks!