[quote name='ras52' timestamp='1432211042' post='2779204']
Ah, but the context is the interval between two notes, not position of either note in a scale. Dropping from C to G is a fourth, and going back up from G to C is also a fourth, no matter what key you're in.
[/quote]
But, if he's playing on an Em, then he's playing the #5th (C) to the minor 3rd (G).