As they both continue to talk...the two of them needed to go back up to breath in some air...until they realize too late that the cover of the pool suddenly closes...
Try as they migh, they were not able to get themselves free, and as the cover opens again, the two of them were now unconcious and drowned...someone from above seems to have noticed the two of them unresponsive in the water...will they rescue them before it's too late?