Edwin Siu ended up spitting on Aimee Chan's face during filming due to the fake buck teeth, reports Oriental Daily.Before filming began, Aimee read several psychology books and watched several psychology related films. Since she had to simultaneously portray a psychopath, she also had to be cautious of her emotions. However, when facing Edwin's 'buck-teeth' look, Aimee frankly expressed it was difficult for her to hold in her laughter. "The first week of filming, I had to watch his mouth and listen carefully to what he was saying, but he hadn't gotten used to the buck teeth yet and kept spitting in my face when he spoke. "Sometimes I had to maintain a serious expression and for some scenes, it's difficult to get the mood back when you had to redo the scene so many times."