[Tarantula Lady]

BTW, I have an alternate explanation why Hei crumpled up the tickets

Spoiler for OAD Ep. 1:

and didn't take the boat with Yin. It wasn't just to spare Yin the discomfort of a ferry trip. If you take a look at the second ED from S1, the lyrics and animation implied that that was the last summer that Hei spent with Bai/Pai before Hell's Gate/Heaven's Gate appeared. So, that summer at the beach was Hei's last happy memory before his life became utter hell.

When Hei and Yin got to Okinawa, Hei was initially quite jumpy and hyper alert. Yin kept insisting that they were safe so Hei started calming down and actually started to enjoy his "vacation" with Yin. When it was time to take the boat, Hei couldn't stand leaving a place where he found some happiness for the first time in 10 years. Of course, it only lasted for about 24 hours. Rather sad, actually.