u shud have played ffx to get my answer:
go to the place where tidus taught yuna how to whistle.. get as close as u can get to the so called "balcony".. arrgh dunno what is called.. and ul see a scene!

if u havent played ffx.. go to the airship and fly to mi'hen.. after u land, walk back and enter luca.. below the save point is the spot that im talking abt..