So all of… everything, Margaret’s death speech, the scream, Cooper waking up, just… all of it hit me all at once and I’m crying. I can’t imagine what filming this must have been like, first of all, with Coulson dying, Bowie dying, Miguel getting sick and dying. David and Mark clearly contemplating their own deaths as they age.

That existential scream at the end marks the climax of the plot, along with Cooper (presumably) having woken up. Now we walk fully into the dark and who knows where we shall end.