It's true, he hasn't broken any since the initial incident -- or, well, he's broken this one, but has never been caught.
"..I don't know," he admits, "I suppose I'd just... be put under tighter surveillance." The very thought exhausts him; for someone this shy, having to constantly be in the presence of other people is as draining as having to run laps with bricks tied to one's feet.

"...or given more work to do, maybe." And be resented further by those in charge of supervision, if he's not shunted off to do busywork and forgotten entirely.
If nothing else, the punishment would be feeling even less like a person than he already does.