FYI all 7 people died; no pulse at the neck occurred between 7:25 and 16:30. The person who lost consciousness after 1 minute 59 died within 8:56. The quickest loss of consciousness was after 34 seconds. It just shows it's not the same for everyone.
It doesn't show that the difference is determined by physiological properties of the subject, since the time to LOC highly depends on the technique of breathing. Hyperventilation with pure inert gas gives you the quickest onset and the lowest possible time, while breath holding (implying a lack of ventilation) gives you the largest possible time to LOC (that can be 4 minutes or more).
It's possible to imagine lots of intermediate conditions between hyperventilation with inert gas and the absence of ventilation. The protocols for exit bags described in PPH/PPeH suggest that you exhale as much air as possible prior to putting the bag over the head, then make a deep inhale when the head is placed inside the bag. If you skip these steps, you delay the onset in relation to the lowest time achievable with hyperventilation. If you do short rare breaths in addition to this, you delay the onset even more, so those monstrous 1:59 could be achieved without having some extraordinary physiological properties.
If you minimize the amount of air prior to breathing with inert gas as suggested and don't slow down your breathing too much afterwards, 30 - 60 seconds before LOC would look reasonable. But 1.5 minutes or more would look weirdly.
Also, hyperventilating isn't really necessary.
It's unnecessary, but the time to LOC measured with hyperventilation can give us some interesting data regarding how fast unconsciousness can be achieved, and it's possible to estimate approximate time to LOC depending on how far the actually used technique is from the fastest method.