Watched it for the first time last night, with the RT.
The dog scene is a powerful scene, no doubt about it. Not gratuitous, not saccharin. My shep-mix just happens to be named Sam, and he got a hug and a Milkbone after that scene, you bet your sweet patootie that he did. Even after all the time he spent barking at the big-screen and trying to join the chase.

And I figured that the stuff he pours on the steps was bleach. Or urine. Something like that.
-dale