From what appears in the media it looks like not so much back-door dealings as realpolitik. There is considerable domestic politics in play where the opposition (Australian Labor) party didn't want to get labelled 'soft on terrorism' by a struggling government which is looking for any message to attack the opposition over the xmas holiday period, particularly if there are any 'incidents' during this time. The opposition have requested that the legislation be reviewed and, one would hope, amended when parliament is resumed.