A tsunami goes through a little door, and plops down a big drop on your face. This tsunami is your tears inside your eye area. The door is your tear duct. The big drop is the teardrop coming down your eye.
Your teardrops always come at the worst times, ruining (るい) serious and/or happy moments. You can't stop crying. it is ruining your life!
Currently there are no similar looking kanji which exist in the WaniKani learning system