Oclean Air sonic toothbrush issue - it turns on by itself, no waterproof.

Here comes the video of my Xiaomi Oclean Air Sonic Toothbrush. I tried to catch the issue how it turns on by itself, however it's hard to stand so many minutes or hours with camera turned on over the toothbrush, so I recorded how the button is not waterproof and water makes it start. Basically, it turn on randomly after the brushing, sometimes in the middle of night, sometimes just after.
It's really annoying, my housemates almost thrown it away through the window...it looks like the button issue which leaks the water into the main board. Sad, otherwise device would be 5/5.

[ThivN]

U know that its pressure button, so its logical that droping water on this would result on starting device?