I think that there is no way that just getting a drink of water is going to hurt his chances of running for president. I think that he was just thirsty and decided to take him a drink, and that he did not have a big scheme back behind it.
Marco Rubio was doing quite well in his GOP rebuttal until he had to stop for water. The entire focus of the conversation after the broadcast was about that. All of his issues and his points were washed away because he was not hydrated. He is definitely a weaker candidate for that moment.
Sometimes a drink of water is just a drink of water. I do not read that much into it, and I hope no one else is seriously doing that, either. I doubt it harmed his chances of running for president. I'm sure he will run for president, and then fail to get his party's nomination for being too extreme.
Marco Rubio might get a lot of the Hispanic vote, but I still think he turned himself off to the older, white, Christian base of the GOP. Though the GOP does need to expand, they still need that old base to win presidential elections. Rubio destroyed his chances completely now.
I do not believe Sen. Marco Rubio has a chance when it comes to running for president, so I doubt his drink of water during his GOP rebuttal did anything to help or harm his chances. I would say his chances of making it past the primary are tiny, so it doesn't matter.