The new routine, and particularly Mother’s new job, means that Luke is left to his own devices more than ever before. And being inside all the time also starts to feel even more constricting. It makes Luke feel less connected to his brothers, too, since he knows neither of them want to be inside. It’s a sign of Luke’s burgeoning maturity when he asks Mother to stop tucking him in. He’s giving up something he loves so that she can get some more sleep, something that’s extremely selfless.