The actor explained that the show's bosses took inspiration from 24 while making plans for the police detective's exit.
McGregor has already filmed his final scenes as Mark after deciding to leave the long-running drama.
Hinting at what fans can expect from Mark's last episode, McGregor told the Daily Star: "My farewell was filmed in real time, like the US show 24."
He added: "You see lots of clocks throughout. It's dark but very cool."
Mark was introduced to Neighbours last year as he investigated Erinsborough's 'Who pushed Paul Robinson?' mystery. He later embarked on a relationship with Kate Ramsay.
McGregor has previously teased that Mark's exit "could be happier". However, the door is expected to be left open for the character's return.
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