Lan Bo is only shortly behind Reno, and as he surfaces, he hears her say something else. However, he understands very little of it this time, and so he pays it no mind. He seats himself on the edge of the hole, not at all looking concerned about what happened just a moment ago. He perches himself up on his tail as he just begins idly playing with his hair while she clearly gasps for air.

This is fine. Most humans are like this. Honestly, if he cared to give it more of a thought, he might be surprised that she actually managed to hold her breath as long as she did. Nevermind the depth; most humans lose air very quickly when they're under panicked attack. Though if she starts to take too long to recover, he might thump the end of his tail impatiently back and forth. When are they going back for the wardrobe?