At the beginning of the game, when you are fleeing Earth, you can see the child
you will eventually talk to running away from Husks. Before you get to the part
where you see Husks climbing up the wall (the first time you shoot at something),
you can see the boy looking below, looking over the railing. When the Husks arrive
and Anderson coaxes you to shoot them, continue to observe the boy run into the 
building and lock the door. The building is blown up seconds later, but he apparently
survives in the vent.