While I don't know why this Lighthouse reacted so strongly to being lit (other then because plot) you could argue that Sheba couldn't just conjure some wind to save her from the fall bcause she was severely weakened by the Venus Lighthouse being lit, since Wind and Earth are opposite forces. Infact, Saturos did claim of being weakened by the Mercury lighthouse when you fight him there. Anyway, I'll be waiting for Lost Age.
While I don't know why this Lighthouse reacted so strongly to being lit (other then because plot) you could argue that Sheba couldn't just conjure some wind to save her from the fall bcause she was severely weakened by the Venus Lighthouse being lit, since Wind and Earth are opposite forces. Infact, Saturos did claim of being weakened by the Mercury lighthouse when you fight him there.
Anyway, I'll be waiting for Lost Age.