It never really shows them breaking through the door, so who knows how long Hodor held out for. And why didn't the children lady just throw that ball, instead of the self sacrifice bomb, that slowed them down for like 1 second, maybe. And why not just hook the sled up to the direwolf and have the direwolf get them the fck out of there.
Besides, the whole this is moot anyway, because the King "branded" Bran, to know exactly where he is. Even if they get out of there, he's just going to know his every location, unless they cut his arm off, or find some other children of the forest that have been hiding out to remove the brand.