Should be fine.
It's not like you'll be using a huge volume of water that's going to fill the cavities during the wet sanding. It's just protection from any that may make its way into them. I always have a dry towel nearby and soak it up as I go when some pools in a cavity.
You need to wipe down the whole thing periodically to check your progress anyway. Nothing should have water standing on it for any length of time really.