This was on my new level 4 sorcerer. I was at maximum health of 41. From the message, it doesn't seem like it should have been a death crit. Especially since all it left was a minor on my right hand.
R>at
You swing a broadsword at a white vysan!
AS: +49 vs DS: -4 with AvD: +36 + d100 roll: +78 = +167
... and hit for 43 points of damage!
Well aimed shot, punctures calf!
The white vysan falls to the ground motionless.
Roundtime: 5 sec.
R>
A dark apparition gestures at you!
CS: +46 - TD: +25 + CvA: +20 + d100: +89 - -5 == +135
Warding failed!
A powerful hit.
... 10 points of damage!
Your finger twitches, then explodes.
The silvery luminescence fades from around you.
The light blue glow leaves you.
The powerful look leaves you.
You become solid again.
It seems you have died, my friend. Although you cannot do anything, you are keenly aware of what is going on around you...
You mentally give a sigh of relief as you remember that the Goddess Lorminstra owes you a favor.
...departing in 10 mins...
