In episode 17, Fung’s (Tracy Chu) 9th time travel, she and Ditch (Vincent Wong) go to find Wai Ye (Pal Sinn) in a warehouse but he sets a trap for them to fall into. Unable to get out, Ditch encourages Fung to time-travel if anything happens to him. But, the rule of time-traveling is only those who time-travel in the portal will remember the past events. Everyone else will forget. Here, they realize they are starting to have feelings for each other.
Ditch: Touchwood, if anything happens to me, remember to travel back three days to rescue me.
Fung: But if I go back alone, you won’t remember me.
Ditch: Oh, that’s right. If I don’t time travel, I will not know anything. Then I’ll only have memories of you from the past?
Fung: Don’t think about it too much. We’ll worry about it after we get out.