Goth will try Dispel (first) + Paralysis, rotate, Sleep + Scorching Ray, rotate, Inflict M. Wounds + Exhaustion. Ends up with his central eye towards Whisper, right-side facing downwards...like his entrails.
I don't see how. The ray has to hit something, and it hit an image instead of the real Whisper. The ray acts as a targeted dispel, so it would only cancel the entire spell if it hit the target of the spell, and it did not.
Goth is only alive until EH returns...but for my own knowledge:
Given the wording of a targeted dispel, if I had said "he targets mirror image" (which means he's targeting the spell, not a creature or object) would that have dispeled it?
If he was a normal spellcaster, yes (note that I have some house rules that require a spellcraft check to identify the spell). But spellcasters don't shoot rays, so the only application of targeted dispel that I can see that would result from a ray is the one where you target a creature or object, not a spell.