Okay, so, Loki’s imprisoned inside a tree for a few centuries, and he’s spending this whole time trying to mind-meld with this tree in order to get it to do what he wants it to. So, he finally achieves zen with the tree, and his grand plan is to make a leaf fall off the tree, poke a passing Heimdall in the eye, make him shed a tear, and that tear will somehow qualify as someone shedding a tear for Loki, thus setting him free. Uh huh.

And, it works. Of course.

“CRACK!” indeed.