Scotley
Hero
However you want to handle it is fine by me. Colin doesn't have to push the Orc at all; all such things are optional effects. I could see ruling that since Colin critted, he might have the option to knock the guy prone instead of pushing him (since he really can't and honestly, I didn't realize that from the map).
Okay I've learned a few things. Pushing is always optional. A wall is blocked terrain and thus no pushing there. A push into an occupied space is also not possible. That's all for future reference. Since both Aislinn and Colin did so much damage, the Orc is quite dead.