In Countries where immigration stamps your passport while departing the country (From my experience, India, Australia, Singapore), would you be considered to have departed the country once you have passed the outbound immigration ?

I imagine the key here is passing the outbound immigration with a stamped passport/any document allowing international travel. A month ago, I flew SYD-MEL on QF74, and passed Immigration in SYD where my boarding pass was stamped, I don't think I "exited" the country at any point.

On the flip side, the local laws of the country still apply once you have cleared the outbound immigration or are in transit at an airport without having cleared the inbound immigration (thus technically still outside the country).
As an analogy, think SIN and a drug mule caught at the boarding gate. He/She has exited the country (or has never entered it) but still, Singaporean laws apply.

So do you actually exit a country when you go past the outbound immigration? or When you board the aircraft?