Judge Alison Lindsay will make the most difficult decision of her term as tribunal chairwoman next week when she rules on whether to expand the inquiry's investigations to examine the role of pharmaceutical companies in the infection of haemophiliacs with HIV and hepatitis C.
Looming over her is the prospect of legal actions by some of the medical industry's biggest players which, no doubt, would be less than eager to hand over sensitive commercial documentation.
On the other hand, if Judge Lindsay refuses the Irish Haemophilia Society's application on the matter, she leaves herself open to an accusation of leaving the job half done.
On the face of it, neglecting to pursue the drugs firms would seem to be an omission, given it was their products - rather than those produced locally by the Blood Transfusion Service Board - which infected the vast majority of haemophiliacs. Moreover, some suppliers have already come under scrutiny at the inquiry, notably Travenol, Cutter and Armour Pharmaceuticals, a part of Revlon Inc.
In the case of the latter, one witness has described how assurances he received from the company about the safety of one of its blood products were "a lie". Another witness has told of Armour's efforts to suppress a less-than-positive safety report on the same product, Factorate.
What justification could there be for not examining this and other matters relating to the drugs companies further?
An answer came yesterday from Mr John Finlay SC, counsel for the tribunal. Quite simply, he said, the matters in question did not fall under the inquiry's terms of reference. There was no clause within the terms, he rightly pointed out, which explicitly stated the companies should be investigated.
However, the IHS argued, the chairwoman could, at her discretion, broaden the inquiry under clause 14 which states the tribunal "shall investigate anything arising outside the State that it considers relevant".
In summarising his submission, Mr Richard Nesbitt SC, for the society, said it was "untenable" to regard the matters in question as not relevant.
The crucial issue will be whether the chairwoman decides to seek discovery - as desired by the IHS - of documents used in litigation against pharmaceutical companies in the US and now stored in a Florida depository.
This does not seem to be an unreasonable request given a group of Irish haemophiliacs have already gained access to the records for a legal action against five companies, an action which was settled last month for £5.3 million.
In support of its demand, the IHS has pointed out that discovery over similar documentation has been granted under the American Judicial Assistance Statute to judicial bodies in the UK and Trinidad and Tobago.
Yesterday, Mr Finlay said he foresaw "at the very least a potential problem", as he understood documents would only be released under the statute to an "adjudicative" tribunal and not an investigative one. He said the tribunal would have to get advice from an American legal expert if it wished to follow this course of action.
This, essentially, is the key dilemma for Judge Lindsay - whether she feels it is worth delaying the inquiry to get such advice and apply for discovery. Last month, when the IHS accused the inquiry of conducting its proceedings with undue haste, the judge remarked that she had to produce a report "as quickly as possible".
Yesterday, she interrupted Mr Nesbitt when he suggested heat-treated Factorate supplied by Armour may have infected more than one person with HIV.
Only one person was infected "as a matter of probability", she said. "We have been hearing evidence for 160 days and that is the case."
More tellingly, on previous occasions when the IHS made applications, she steadfastly stuck to her counsel's advice. There is no reason to believe she won't do the same again.