What do police officers do besides their main duties?

besides 

นอกเหนือจาก

What's your emergency?

They took this opportunity to teach the young fellow.

to take the opportunity to do something

The police showed up at his birthday party.

ตำรวจปรากฏตัวที่งานวันเกิดของเขา

show up 

ปรากฏตัว