Although I cannot remember where I read it (and this accident has been discussed on multiple forums) I am quite sure that someone involved in the recovery posted that she was found on the far side of a tight restriction, having removed some of her gas supply to pass it on the inward leg
This was posted on CDF, and reposted here [by me] attribuited to Ken Smith:
I was one of the divers who assisted with the recovery of Agnes from Tank Cave. We have discussed what we should say and have written the following. This is a very sad time for us all as you can imagine.
Ken
On Sunday 27th Feb, Ag was exploring in Tank Cave, using sidemounted steel tanks. She tied off to the existing cave line and reeled out.
Ag unclipped one tank to pass through a series of restrictions. At some point she made the decision to leave this tank to make further progress. Ag continued to explore before turning to come home. Coming back in silty conditions, she was unable to navigate a restriction. She ran out of air before she could return to her tank.
Her body was brought to the surface by cave divers on Wednesday 2nd March, co-ordinated and supported by the South Australian Police and with help from the State Emergency Service (who are volunteers). A full investigation is being undertaken by the Coroner.
Ag was an inspirational diver who accomplished many impressive feats in a short space of time. She will be sorely missed by her Mum, Dad and many friends and buddie