Over the last few weeks work has been going on at the station, in advance of protective service officers shortly being deployed for nightly patrolling from 6 pm to the last train.
The PSOs will presumably be spending a lot of there time on the down platform ie the platform for trains heading out of the city, with the building on that platform being modified to include a holding cell! However if they are after a cup of tea or have a call of nature they will need to cross over to the building on the up platform. One would expect that as part of their patrolling they will venture over to that side as well, which will take them down the underpass on Koornang Road.
The roll out of PSOs to stations has been going for some time, suggesting that Carnegie wasn’t a high priority – but don’t forget that a little under 5 years ago a fellow was stabbed there at 11 pm on a Monday night – one of the incidents involving Indian students that damaged Melbourne’s image and led to a fall in the number of overseas students (see here).
Carnegie Life 
Wow. I had no idea anybody was stabbed in Carnegie.
Heard on the radio tonight that PSOs are starting at Carnegie station tomorrow night.