Don't forget to read back the logs from a while back.
The same question has been asked many times in a short time, and everyone has answered it.
When you first face off against Tank and Scar at the thieves' camp, you either have to give in to Tank's temptation and satisfy his libido, or you have to win the battle against Scar. If the event doesn't occur even if you give him medicine at this stage, it's already too late or you have to start over from the old data.