In fact, the Medicine God Valley disciple who was captured by the Myriad Ghost Ancestor did indeed experience a torture akin to a lingered execution.
To avoid being blown up by Huan Qingyi's Sword Flowers, the Myriad Ghost Ancestor cut off a large chunk of flesh from his own body.
If a mortal had a piece of flesh cut off, they would have died on the spot, but for someone of the Myriad Ghost Ancestor's caliber, it would not be fatal, though it would cause significant hindrance and was akin to sustaining a heavy injury.
Therefore, at this time, the Myriad Ghost Ancestor had to cut the flesh from others to repair his own body.
There were many secret techniques within the Ghost Path for repairing the body, and the Myriad Ghost Ancestor was naturally well-versed in them.