Space here does seem to be rather tight!
When you’re flying a big jet, space is always tight. Looking at the google images of the airport, there are no obstruction clearance lines (they don’t exist everywhere, but are helpful when they do - Tullamarine), and there actually doesn’t appear to be adequate room to pass behind any aircraft at or near a holding point. Just because ATC have cleared you to do something, does not mean that clearance will exist.
It reminds me of a little game that the last incarnation of Ansett used to play. Many of their aircraft, when cleared to a holding point, would stop short, with their tail over the obstruction line behind them. You’d then have to stop, and/or get ATC involved to get them to taxi forward. I wondered if it would all end in tears…
I saw Air India have a very near miss with this sort of thing in Melbourne. A pair of 737s were at the E holding point, with the second over the obstruction line. There may have been sufficient room if they’d bunched up a bit, but… In any event, the AI 787 thought that he’d go off centreline, and around them. We called that there wasn’t room on the radio, and ATC told him to stop. An airline to avoid.
And a second one to avoid, at all costs, is Asiana. They had a very serious go at running into my 767 in Singapore. Utter incompetence combined with arrogance.