Lastly - I wouldn’t be diving, let alone instructing, had I not been diving with a buddy who quite possibly saved my life in Key Largo two years ago when I myself had an out of air emergency standing 94’ down on the deck of the Spiegel Grove. (I’ll spare you the gory details and just say that a buoyant emergency ascent would’ve left me in a bad way) Ironically that you mention: His alternate air source wasn’t functioning, either, yet we still managed to ascend and make all required stops passing a single 2nd stage back and forth. Believe it or not: Training kicks in and task loading becomes manageable once you grasp the severity of a situation. This is why we train.