yitayningwut,
R.Y.H. Henkin is completely unreliable, including in his reporting of his grandfather Hagoen Hatzaddik Harav Yosef Eliyahu Henkin ZT”L’s positions — which he very frequently is completely at odds with himself. (This is aside from the fact he is not accepted for his positions and reliability in general in the Torah world.)
The only thing that footnote then shows is that Harav Schachter shlita said that Rav Soloveitchik zt’l allowed this only in dire circumstances (“of duress”).