DozyW #273:
There is no issue with the transcript as regards Capt Collins and F/O Cassin: "When I listened to the tape recording myself, which I did on two occasions in New Zealand, it became clear that the only two voices which could be heard without difficulty were those of Captain Collins and First Officer Cassin" (Royal Commission's Report, page 36). Mahon did not take issue with anything in the transcript that was attributed to the captain or the F/O.
Of course it's very easy with the benefit of hindsight, but the issues with the VMC/AINS plan were known to Captain Collins before he went below MSA. Although he had not experienced sector whiteout before, he knew that visual perception could be affected. That is probably why he locked back onto the nav track - but in doing that, he also knew that he had received conflicting information about the waypoint and hadn't checked it.
A good pictorial summary of what happened is at Annex D, Appendix 3, of Chippendale's report:
Chippindale Report
If you look at that 3D presentation, it's difficult to understand why he decided to go down in that situation, even if he thought Erebus was 20nm to his left. (Ironically, the track of his two descending orbits is engraved onto the flight safety award named in his honour.)