And also, if you are intubating the person, they are probably pretty close to death. And then on top of that you paralyze them (with a medication, temporarily). So you are stopping their breathing. You have a few seconds in these people to get their lungs connected to mechanical ventilation. From what I've seen, if you don't, the outcomes are very bad.

This may be somewhat different from the typical intubation case, for example prior to surgery. Where its a generally more healthy person who has not been hypoxic for hours or days and is not at the last of their reserves...