...I don't know what to tell ya. You're effectively asking me to choose between what I saw and what you say.
There was no injury involved - this was on Normal difficulty, and wouldn't explain the first one-shot regardless.
It wasn't an Officer who dropped me with a single bat'leth swipe; it was a Swordmaster. All the Officers were pushovers, as a matter of fact.
The character concerned was wearing Polyalloy armor (though possibly Mk I - can't remember).
I'm not by any means new to the game, and I have a fair amount of situational awareness. I enjoy ground combat, and generally don't get defeated multiple times in a single mission unless I'm playing Elite.
So... yeah. I appreciate you suggesting alternate hypotheses, but so far they don't explain what I witnessed.