The words of the rabbi and the words of the student, whose words do we listen to?

From the meal with the Gra, we were saved in Simchat.
1 arrived and said that he heard at some conference on medicine and halacha that a certain professor, Rabbi Shlomo Zalman Auerbach, told him about Rabbi Yishmael 253 who took the head of his friend who had been beheaded and wept bitterly, etc….
After all, there was a 23rd century, and how could he be defiled to death?
And he replied: Apparently the Romans had a kind of etiquette of a last wish and the like… and when they saw Rabbi Ishmael busy with the head, etc., they let him go until he finished, and the protection of life, even for a moment, postpones the prohibition of the impurity of a dead person for the priesthood.
And from this we learn how much effort must be put into saving the sick, even for a moment’s life, etc.
The Gra Nebenzel said that in his opinion it was in the house and since the deceased was buried and all those present there are defiled by the impurity of a tent, there is no prohibition against adding impurity, and therefore there is no problem with taking the head [Rabbi Yishmael was forced to stay in the house where the Romans were killing] and on the contrary, it encourages more people to give a good eulogy.
 
Who is right, the rabbi or his student?
Or 2?