I think Fl/Lt Hammett's mention was from an aviation forum I looked at, though I see he is not mentioned either in the Australian War Memorial website "Roll of Honour", so it could be a mistake that he was KIA - nevertheless, he was in Sqd Ldr Liversidge's crew, so you can follow the bouncing ball from there if you wish to delve further.
It seems that Fl/Lt Hammett was wounded when the plane was shot down but survived and then evaded capture, linked up with the local AK and was with them when the Russians finally turned up.
"Squadron Leader Liversidge, a flight commander of No.178, was also killed on the 16-17 August,1944, when the Liberator he was navigating was shot down by an enemy fighter near Cracow while returning from the crew's second delivery flight. from this aircraft F/Lt. Hammet*, although wounded by bullets in the arms,legs and left side, safely parachuted and hid with a partisan group until the area was occupied by Russian forces." End quote.
*fn. F-Lt A.H.Hammet, DFM, 400754; 178 Sdn RAF. Chemist apprentice; of Red Cliffs, Vic; b. Melbourne, 24 Jul 1921.
There is a poster in that thread who claims that the mission was actually to Piotrkow, but a) I tend to believe Commonwealth War Graves records over a self-proclaimed expert and b) that poster in another thread wrote about the "so called Ghetto [Uprising] and claimed that the Ghetto Uprising "actually was not an uprising", i.e. is not a source which has much credibility.