Encountered Stray Dog and Animal Control Was No Help

Today I encountered a stray dog in a random parking lot within the city, and from its appearance and given the heat, it needed medical attention. I called Houston Animal control, which linked me basically to the 311 phone-line, and I gave them the location and they said "don't wait around there is no ETA."

I have a soft spot for animals, and I tried to coax it with food and water so that I could take it to a shelter myself. However, it was very skittish, and eventually ran through a fence and I couldn't follow it.

Is there any other organization in the area that could be more helpful in these types of situations? Thank you in advance.