At the coffee shop..
Saadiyah told Nathan to go serve a customer their coffee. That customer was Jun. When Nathan was about to bring Jun's coffee, Saadiyah may have tripped him on purpose to talk with Jun. When Jun got soaked with hot coffee, he found himself blushing instead of getting angry. Even Nathan couldn't look Jun in the face without blushing.
This is the lazy version of
Part 4: Realization.
