Day one of Prof Ian Temperley's cross-examination and already holes are beginning to appear in his defence of his actions.
Over the past two weeks of direct evidence, the retired doctor has put much emphasis on his isolation within the medical profession, and on how he was forced to turn constantly to the UK for advice on the HIV and hepatitis C crises.
When asked why he did not develop guidelines on product use as soon as he became concerned about AIDS, he said he was waiting to hear from the UK as to what doctors were doing there.
When asked why he did not ban the use of non-heat-treated concentrates after it was shown heat-treatment killed the AIDS virus, he said the UK doctors had yet to make a definitive decision on the matter.
It was the UK haemophilia treatment centre directors to whom to looked for help and whose line he "more or less followed".
Yet, as the tribunal heard yesterday, Prof Temperley had a somewhat selective attitude to their advice.
In June 1983, the UK haemophilia directors recommended that locally made cryoprecipitate be used in preference to commercial concentrates in the treatment of children and previously untreated patients.
Defending his disregard of this advice, Prof Temperley claimed yesterday that the UK directors did not always follow their own recommendations. But if this was the case, why did Prof Temperley seek their advice in the first place, given they weren't implementing it themselves?
The tribunal heard that when Prof Temperley finally drew up guidelines on product use in November 1983, he did not inform his colleagues in other treatment centres around the State, except for his counterpart in Cork. He said yesterday that maybe he should have sent the guidelines out but he was still "unsure" about the correct advice.
In another important development yesterday, Prof Temperley admitted his concern about AIDS stretched back to late 1982 and not early 1983, as stated in previous evidence.
The difference of a few months may not seem like much, but it is. A retrospective study of certain HIV-positive severe haemophilia A patients suggested a quarter were infected between 1983 and 1985. If this estimate is applied to the 105 haemophilia A and B patients infected with HIV - and there are reasons to believe the proportion infected after 1983 is greater than 25 per cent - it means at least one haemophiliac a month was infected in the two-year period up to 1985.
Every month counted, therefore, in quite a profound way. It is in this context that Prof Temperley's response to the AIDS threat is being scrutinised.