May this be a rather awkward question and venture: I will have a one night layover at ICN and, during this time, would like to obtain a washlet, Toto, Samsung, Panasonic etc. Due to voltage, Korea seems to better place than Japan for that.

The question is where to get it around ICN or in Seoul (City Air Terminal - I would only go downtown if absolutely necessary.) that is easily accessible - my time is very limited, arriving at around 5 pm, leaving at 2 pm.
A random bing or google search wasn't very helpful.

Thank you.