In fact, the whole Final Chapter of Zero is one big string of Awesome Moments of Big Damn Heroes, one after another. Dieter and Mariabell playing chicken with a missile launcher to rescue the SSS is another great example.
Randy's Roaring Rampage of Revenge at the end of Chapter 3 where he Almost successfully wages a one man war on Red Constellation, until he runs into Shirley
Proving that Oh Crap moments can indeed be awesome, the scene where we learn the true purpose of the Geofront, as the entire country of Crossbell is transformed into a massive alchemical circle which awakens KeA's full power.
Villainous though it may be, the scenes of the Aions completely annihilating the military forces of Erebonia and Calvard is damned cool. Aion Type-Alpha tanking one Railway Cannon shot and destroying another is also damned awesome as we've spent two games hearing how those guns could annihilate Crossbell if they were ever fired at it. Then it goes and makes sure those weapons will never be fired again...
Zeit in his Sacred Beast form saving Lloyd at the end of the Fragmentary Chapter.
The entire liberation of Crossbell sequence in the Final Chapter. Actually, pretty much the entire Final Chapter is a long string of Awesome, mixed with Heartwarming and Tearjerker.