Layla swam through the murky water. Carrying another person on her back makes her swim really slowly. But, she could have sworn that the boat have been here somewhere. When Michael and Brava escape the water impact they should be around here.
Looking around, Layla could only see dark trees and dark water. Add the rain on top and she didn't know how she could find them in this situation.
'Could they have already left?'
Although she has been pretty harsh with Michael, she didn't think that the boy would leave her out here. Brava could potentially suggest that idea but, she doubts Michael would go with it... after all this is the guy who save her multiple time. He wouldn't leave her here, right?
Then what's the problem? The refuge? why did they do that? They even abandon their friend?