This actually had happened when I was about to relieve a medical officer from his duty at night. I was appointed for the night-shift and had to relieve my co-worker from his evening shift.
Which way I greet a person whom I am meeting at night 10 o'clock (or for that sake up till midnight). One ore thing, this is the case wherein I'm meeting that person for the first time in a 24-hr clock (day? night?).
Good evening doc! What's the order for the patients tonight (or is it today?)?
Good night doc! What's the order for the patients tonight (or is it today?)?
Good astronimical dusk (huh!) doc! What's the order for the patients tonight (or is it today?)?