Some misinfo posted by Starbright above. Tolgrumm knows the specifics but to clarify.

1. The healing surge of SotB is triggered (any creature or PC).

On your affects list you will see a visible Spirit of the blade buff with a duration. You cannot recast SotB until this buff wears off, I assume it is the 'you are stunned' counter. The duration of this debuff tracker was fairly short (or may have matched the original timers duration when sotb heal was triggered.)

Two scenarios can happen at this point which will stun you at set your HP to 0.

2. Fight and kill any PC in any way - Stunned at 0hp.

or

3. Kill a (similarly named?) mob to the one you were fighting at the time SotB was triggered - stunned at 0hp

My scenario for 3:
I fought Quarissa in Hamsah along with a summoned devil. SotB was triggered by her devil, She fled. I continued on my way to Outlying villages, killed a demon/devil(?) there. Stunned at 0hp, next demon killed me. Looking for the log on it. I posted it on the bug board of officials
at the time, it was never acknowledged so I believe it wasnt seen as a bug.

After this death I did not intentionally fight or kill anything while under the 'you will be stunned' debuff as it wasnt worth the risk. Prior to this I completely disregarded the debuff thinking it was tied to PC's. So it definitely did not *ALWAYS* happen. It could have been tied to bloody timer for a pk fight. I could not say for certain.