Astarion has no idea why his tadpole has not begun to transform him into a mindflayer. When he arrives, it's his immediate, panicked reaction. After all, he is far from Faerun, far from the protection of the artifact - it should be metamorphsizing him, turning him into a monster. Again. It never happens - no fever, no tentacles. Yet the tadpole must still be in his brain or else he'd be burning in all this sunlight. There are no answers to that particular question (and he certainly won't be asking - people tend to stab first when you tell them you have a tadpole in your skull), and so his focus shifts to making the most out of this particular situation.

He doesn't help pass out the water (because why should he?), but he mingles near the rest of the other newcomers. Then one of the farmers begins to weep black tears. They weep so grossly that the tears flick from the individual's face and land on Astarion's shirt, dampening it with something dark and ugly.

"What in the hells."

He rears back instinctively with a high pitched sound, which means he runs directly into the familiar wizard (who he ordinarily would have been able to smell a mile away).