An ex Lanc rear gunner once told me the reason Gibson went was because 'he got too cocky'.
IIRC Gibson hadnt had that much time on the old Mossie.
That night he deviated from the planned route home. I also thought that when wreckage was found only a few years back there was evidence of a problem with the fuel selector.
Mossie pilots knew the problems re recognition and in the words of Jack Currie ( Lancaster Target) 'gave them a wide berth'. Them being four engined RAF heavies.
It would seem unlikely that Gibson would have strayed so close to become within range and most probably he would have been at a different height as well, that coupled with his deviation makes it unlikely.