[Jovus]

However, I might argue that Blink would work against all the Fireballs, since this action is happening nearly simultaneously (within a single second), unless he happened to Blink somewhere still in the line of fire.

Not that this is in the rules, to my knowledge. It just seems like a need extrapolation, and that's one of the things I enjoy about GURPS - the way the system can be stretched and prodded, but still maintain its consistency to a high degree.