That's how a death guard is made.
4 seconds sound clip from the The Beastmaster movie soundboard.
You can hear this line at 01:12:53 in the Blu-ray version of the movie.
Quote context
[...]
- No!
- Come on.
- Now I know why there were no guards out front.
- That's how a death guard is made.
- Extreme torture transforms the man into a wild beast.
- We have to steal those keys.
- Stealing is best left up to thieves.
- Watch. The Jun priests will encase his body in deadly armor.
[...]