The power of a weapons the heavily-invested parent employs varies with
timing and circumstance. The most aggressive attacker knows how to use
it, and when, and where. The subordinate one, whose role is obvious if
you have a sense of what I am discussing, has no choice but to stay and
endure the brutal abuses under some circumstances.
Just an instance of When: dinner time. For a juvenile, one of whose great
pleasure is enjoying food(no sexual pleasure yet), he is not able enough
to  afford to evading an attack just by slamming the door hehind him and
go to a restraunt.
Another possible case, though I hope it might have been only an imagination.
When he's got a top rank in an exam, and he is telling his opponent of result
with the prospect of an encouraging word or an awarding promise of whatever
kind, and, instead of any positive response, he is retorted with something
like "somebody is better than you in maths or something else". This will
do, no further ado needed. The common sense is that a gourd of cold water
is more effective when one is heated. Sure enough, there is always someone
whom he knows well and who is better at certain field.
The most aggressive individual is always good at finding a proper weapon, how to
use it, and when and where. Some "conventional weapons", when deliberately
utilized, might well be mass destruction.