The parent did not say "we know there is no way back now, there is only doom ahead."

They said "every step on our current trajectory could represent a threshold triggering processes past which there is no return", and while it's left implied, the implication is that maybe we should consider stopping our current trajectory an emergency, much in the same way that someone who realizes they're as yet intact within a minefield might stop blithely strolling along even if the next step is only a marginal risk, not a guarantee of disaster.