Exploit bypassing WorldGuard's use:deny on doors.

Given the following setup :







The whole area is protected with a WorldGuard region and the region flag "use" and "build" are set to deny.

So I have this player who does something that puts him on the second half on the door with the head through the block above the door, then he can just walk off the bottom half of the door to the other side with some damage, effectively bypassing the use:deny on doors.
He can also use the same process to get out of there.

If the door is placed like this :


He will still be able to get on the first half of the door with the head through the block above the door, but he won't be able to walk off to the other side and also won't receive any damage.

Any idea how he's achieving that? It's really pissing me off and he won't say how the f*** he's doing it.
He first said it was lag, then he said it involved slabs and stairs, but he might as well have been talking shit.

It's also worthy to note that I have NoCheatPlus enabled.

 

Bamp?

 

[19:09:05] <K> Okay i'll tell youuu
[19:09:11] <K> You'll see
[19:09:15] <K> it's very very simple
[19:09:40] <K> When you open a wooden door, it opens, then closes because of we, right?
[19:11:13] <K> Then, when it's open throw a ender pearl. You have approx half a second to do it
[19:11:15] <K> No, less
[19:11:22] <K> Then, using a slab or a stair
[19:11:31] <K> You'll be able to move trought them
[19:11:53] <S> I think I saw you move through glass too.
[19:12:12] <K> I think it makes you able to move through many slabs without taking damage
[19:12:13] <K> No
[19:12:26] <K> i've never went throught the glass
[19:12:34] <K> WE is waaaaaay too fast on this one.
[19:12:42] <K> I tried tho. Never worked
[19:13:22] <K> Doesn’t work when there's a metal door or a complete block over it
[19:13:45] <K> that's all :3

I think that's it?