Really? You don't think it might be a sign of being thirsty?
I have actually never heard this claim before.
I think it is a lie. Can you prove this?
Trump was merely worried about Hillary's sharpshooters that could be stationed anywhere. A .50 calibre rifle can shoot a mile accurately if you have a good shooter. Far less than a mile was necessary in the debates. Trump wasn't going to do any shooting, but the Hillary-record shows that she was behind or associated with lots of "accidental" deaths.
Trump bravery was tremendous. He was probably drinking water to replace what he was losing to his undergarments in sheer terror of the evil of Hillary.