I don't get your drift. Given the events, anything is possible.
1. The last thing Australia wants is for this to end up at the ICC, so it has to be dealt with.
2. An inquiry was established and the findings published.
2. Brereton will know that Senior Officers are under scrutiny in all of this.
3. So could Politicians ( If they were putting pressure on Senior Officers )
4. If things were to collapse during the course of the Investigation phase / or even further forward at trial stage, it would kick the ICC into touch.
This would potentially.
1. Save the necks of any implicated Politico's
2. Save the necks of Senior Officers
Of course - That old adage of '' Lessons will be learned '' will be repeated ad infinitum.