The surface of the 12-foot pool bubbles like a hot tub while instructors below signal to a group of dive students using a series of hand signals on how to inflate their vest. One by one, each student slowly starts floating to the surface. The instructor signals the students to deflate the vest and again, one by one, they return to the bottom. Lined up along the bottom of the pool each student takes his turn floating up, then sinking down. The entire exercise from start to finish looks more like a wave at a football game set at super slow motion than a dive class.