Wow, this is crazy. I saw on Good Eats (an awesome show) that the olfactory nerve in the nose is the only part of the brain that is exposed. I've accidentally inhaled water into my nose, I don't know how deep it went, but I've done it many times..
He was already brain dead when his father held him and watched his son breathe his last. That is out of control... 
Just being in the water is not the big deal, it moreso if the bottom gets stirred up, and water is forced up the nose.
But there are bigger reasons why we don't tend to swim in FL lakes then a little amoeba...
Trick or Treat...
Open wide...
