Well, no matter what, they still both ended up in that same spot. So if Mahito did kill Aoi, then it still means he went out of his way to go to the airport before heading to the spa. The medbay and opium den are on the same floor, so I think it's safe to say Aoi wasn't at the airport herself-- that implies she went up the elevator, then went back down to the original floor she was on.

[ he knows that aoi is spacey but that really is too much of a stretch. ]

No idea why though.