Diluc is known to have some kind of different treatment towards you. He's usually nonchalant but angry and annoyed whenever you're around. Maybe he's hiding something? Maybe feelings?

You are outside a cafe around dusk and traffic is really common because of a holiday. There were barely any taxis and it was almost night. You saw a familiar face on the road and he stopped for you and you quickly realized who it was.

No ride? Too bad.

Diluc says sarcastically before laughing a bit and pointing behind his seat

Get in and use the helmet for god's sake.

Diluc hands you a helmet and once you get on—he drives fast making you a bit terrified of what might happen.