Casting Through Closed Doors/Magic Weapon More Powerful Than it Should Be

[Solance]

One exploit, one bug.

Casting Through Closed Doors
I came across a closed door in Act I Inferno, Cathedral Level 4 and saw a green pool coming out under the door, so there was a champion or rare behind this door. Not wanting to jump in blind, I tried firing Arcane Orbs with the Celestial rune at the door. Even though they exploded, the monsters behind the door didn't take any damage, which was to be expected. Then I tried to cast an Arcane Hydra behind the closed door and succeeded to my own astonishment.

http://dl.dropbox.com/u/7925/Screenshot002.jpg
Edit: http://dl.dropbox.com/u/7925/Screenshot003.jpg - different door, better angle, visible Hydra kills invisible mobs.

Not wanting to wait for my Hydra to kill the pack, I thought 'what the heck' and tried to Teleport through the closed door, which worked as well. I did some damage and Teleported back behind the still closed door while my Templar enthusiastically commented the action which he could neither see nor participate in.
On a related note: I was even able to pick up a health globe through the closed door.

This is very circumstantial but exploitable (just leave the first door closed and kite any elite pack back to it).

Magic Weapon More Powerful Than it Should Be
Magic Weapon increases damage by more than 10%, which is what the tooltip says. I figured out exactly what's going on. It's being applied twice, in two different ways. It applies a 10% bonus that adds with other general damage bonuses, and a second 10% bonus to everything. So with Glass Cannon 15% and a Familiar Sparkflint rune 12%, I'm getting 15%+12%+10% = 37% bonus, with another multiplicative 10% on top, for a 50.7% bonus. With just Magic Weapon, I have a 21% total bonus (1.1*1.1 = 1.21).

[Lilleso]

Magic Weapon increases your weapon damage by 10%(15% with FW), not all damage. As such it is applied before other multipliers such as Intellect.