Athan didn't return, stayed to fight more and get rewards as he saw that Tiana and others were still training and haven't broken through yet.
After killing Goredon, He started moving again while using his detection barrier, but he didn't encounter another enemy in the ten minutes before the trial teleported him.
Just like this, He continued killing, and when he killed his fifteenth opponent, He received a voice in his head.
[ You have completed fifteen kills, From now on, you will receive better rewards at every kills. ]
" Better rewards? Well, I can't wait to see them. "
All he received until his fifteenth kill were the fruits that increase one's soul strength from 1 meter to a rarely 2 meters, so he wanted to see the better rewards.