I recently noticed my evaporator box on my 96 blazer was cracked and leaking quite a bit of cold air. I taped it up nice and now i can no longer feel any air leaks and the a/c works way better.

Now, im guessing that the box is the only thing containing the air and there is supposed to be air moving aroung through the evaporator core inside the box (so if the box was cracked it would leak air out?). Am I right?

Im just worried there might be a broken part inside the box that is causing air to leak out of the cracked places in the box.