Thanks to A World's Legacy directly using people's souls Akiol held a unique advantage of recognizing players in the real world. Additionally thanks to his technique of {Star Guidance} Akiol could sense souls in a pretty large distance around him.
Although the range was reduced thanks to his condition, Akiol was easily able to sense most of the stadium's people. Admittedly the thousands of people at the seats made it difficult to single anyone out, but thankfully Travis and Igneel's souls were not within that crowd.
Additionally their souls stood out a lot more. Travis' was unusually bright compared to others. Igneels also looked like two souls circling together. You could compare it to a planet and its moon.
Akiol stopped at a doorway and peered at the souls of the two missing members. Oddly there was nobody else inside. If the words of Nimin were to be believed they should be having trouble with security.
