[Glirdan]

Hmmmm. That is possible because he's only fighting one Nazgul and not five like he did at Weathertop. The only thing (that has been disscussed many times before) is how would Gandalf turn into Gandalf the White. Perhaps at Amon Hen, he could have fallen trying to protect Boromir and then maybe Boromir would have survived. Or maybe he could have fallen off of Rauros somehow and then Boromir would have died. That is a very contraversial topic. I say that perhaps after fleeing Moria, the Balrog could perhaps have chased Gandalf and then they fought and both died there while the Fellowship fled to Lothlorien. There are endless possibilities with this question.