Gandalf's First Sacrifice

[Morsul the Dark]

The Thing is this, Gandalf would have been brought back, however more than likely as a different character(Only revealing himself as Gandalf at the appropriate time, also remember Why the Eagles helped Him, He had saved the Lord of Eagles from a hunter.. or at least healed a wounded wing(Not near my book at moment.)

Gandalf may not have noticed the eagles coming but He would have taken out the orcs.

If somehow he didn't win and fell well then as I said he'd come back hidden. Because if Saruman Thought Gandalf was gone he'd probably be emboldened against Sauron without having to hide his intentions from Gandalf. Then there is also the other aspect of Gandalf's Ring what would happen to if one of the orcs had got hold of it?