The sergeant is looking for food. Birds, mammals, fish, most all vertebrates, rub, peck, groom the face of their parents when young, then other animals when developing, in an attempt to get food. Insects and arthropods also hang around the face of cattle/horses/dogs/humans for the same reason. What often looks like kissing is one animal looking for food or moisture near the mouth/nose of the other animal. The reason your dog "kisses" your face when he's happy is that evolutionally, they have imprinted on face+food+happy.
I only just started watching these videos, but the thing that impresses me is how much control the turtle has when he's on the skateboard. He understands how to maneuver, he can turn and stop and speed up and back up, it's really amazing. Turtles are way smarter than people give them credit for.
