It is simply what a lifetime of busy mornings does to a person: it teaches them to process a child’s clinginess as a minor obstacle between them and the door, a thing to be soothed and set aside, not a signal to be heeded.

And if Lily had not looked toward the kitchen, if she had not, at six years old, had the instinct to check whether she was overheard, Marcus might well have followed his own instinct all the way out the door and onto the plane, and everything would have been different and worse.

He has thought often, since, about all the children whose parents do not happen to catch the glance, who follow the busy-morning instinct out the door, who reassure and detach and go, and never learn what their child was trying to tell them.

The margin was fifteen minutes and one flick of a little girl’s eyes.