LAST EDITED ON Aug-26-08 AT 05:15 PM (EDT)
 
There are many others - too many to list here, probably - but the first that came to mind was in Symphony 1-07 when Saionji meets Liza in the B5 core shuttle train and forces her to step onto a new path with a startlingly sudden and bold act of his own. I can still remember my moment of reaction (roughly, "HOLY $%^!!") when I first read it.

I should also mention the scene just before it, in her quarters, where we see her utterly broken and sincerely (though not yet publicly) repentant.