A mercenary captain rolls "multiple injuries." However, one of his "injuries" is "sold to the pits." It seems odd that he can't be captured but he can be taken by slavers. Is there an FAQ out there that says any different?
Here's the multiple injuries text for convenience:
16-21 MULTIPLE INJURIES
The warrior is not dead but has suffered a lot of
wounds. Roll D6 times on this table. Re-roll any
‘Dead’, ‘Captured’ and further ‘Multiple Injuries’