not sure if its a bug or something, but the onion thats supposedly in the area when talking to Akemi and Hikari isnt where it says its supposed to be in the walkthrough.
Yep, it does seem to be there, it's out of focus, and hard to spot, but it's there. It's just to the right of where Akemi stands while she's on the phone, partially obscured by the door frame. (Unless it's a bug. It unlocks an onsen type picture, so check to see if you've already unlocked it I guess.)