Over-thinking things that should not be over-thought

So, in one of those sleep deprived hazes I started think about the mountain lake on Deathwater Island within Narnia; as chronicled in The Voyage of the Dawn Treader. Okay, the water turns anything it touches into gold. Lord Restimar died when he dove into it.
I was thinking about that in particular, and was wondering if he would have felt any pain when his hands turned to gold before his head. Would the nerve pulses travel faster than the speed he entered the water? Would his brain feel it.
But then, his brain never touched the water. It was in his head. Then I thought some more.
Gold, as far as I know, doesn’t let water pass through it. So really, it should have changed the surface of his skin and his hair into gold. Probably painful, definitely unhealthy, but if he never opened his mouth, that should be it. Gold is also somewhat flexible if it is thin, so I would think he would be able to swim his way out. Possibly blind?
Or we could just say it was magic.