What was that?

Gaia and Roark were in the boiler room of the Queen Mary when Gaia hears this wierd noise that sounds like something just fell. Roark heard it too and they check the place where they heard the sound come from. They didn't see anything though, but Gaia was scared. you can tell by her facial expression.
this scene will be in the pokesiders parody episode 2
Roark belongs to Satoshi Tajiri.
Gaia belongs to