1 Kitty, 1 Doggie.
Ya made a snap decision based on current knowledge and gut reaction. Stick to your decision and keep the hope that someone else is able to help.
Jus sayin... 
You should just carry a gun, you can remedy the situation by just putting Fido out of his misery on the spot. Besides, how many fricking animals are people expected to care for?
I actually wondered how long he was going to survive with loaded garbage trucks flying in and out of this place.
Sadly, if I would have discharged my sidearm, I would have garnered the attention of the Sentry guarding an Air Force Base installation entry point. Not such a great idea being its 100 yds from the runway either. 
Shitty situation to find yourself in. I'd probably have taken it to the pound to be euthanized if it looked in pain. Better to put it out of its misery.
I actually tinkered with this very notion. But I was afraid that once I picked the poor little thing up, if he wasn't all that hurt other than his front leg, I'd be in one of my aforementioned scenarios.
BAH! God damn people. There is no such thing as a bad dog, just bad owners. 
for all the stray, lost, abandoned, and/or abused animals.
Some strays become heros.
Gramps
I don't see where you had much choice, unless one of your current pets is a gold fish.
In that case, flush Goldie and make room for Limpy.