If you're certain that it got inside the switch, (like literally inside the switch, where the springs can have water) just leave it there drying and hope nothing happens. If a bit of water just touches the outside of the switch it's no problem.
I'm no keyboard expert but I had some experience on my previous Filco.
Also, using the plastic cover always helps and avoids spills. Like right now I just spilled some water but I had the plastic cover on.