"It is learnt the doctor was headed for India via Kuala Lumpur, on a one-way air ticket, but had not resigned from his job at the Gold Coast Hospital. " A two way ticket costs just 20 % more than a single way ticket. If you are going back within the 180 day time then you will 99% purchase a 2 way (Return) ticket.
But if you purpose is finished in one trip then return ticket is not needed. Q Why did Mr Haneef buy a single way ticket even if you have not resigned? A I was not supposed to go back.