Comparing it to X flights maybe correct from a greenhouse emissions standpoint, but extremely misleading from a safety perspective. A jet emits that co2 spread over tens of thousands of miles. The problem here is it all pooled in one location.

Also that statement of 70 meters seem very off, looking at the size of the building. What leads to suffocation is the inability to remove co2 from your body rather than lack of oxygen, and thus can be life threatening even at 4% concentration. It should impact a much much larger area.