Meng Xiuluo felt surprised, why would these guys show up here at the third watch of the night, and they were here to capture them. This was clearly a premeditated action, and what's more, a large group had come, which seemed unreasonable. Could it be that they had captured other disciples of the Dragon Slaying Clan? It was highly likely. They were stranded here, so why couldn't other disciples also be stranded here!
She also knew about Longhun's actions against Zang Di, because Longhun didn't want to raise a rival in the hundred and eight islands, so he tried his best not to let Zang Di control the island, and found ways to help Scorpion Witch, Zang Di's adversary, using the latter to deal with Zang Di. Probably because of this, Zang Di particularly disliked the people of Dragon Slayer Island.
Indeed, they were a bunch of savages, leaping up with the intention to grab the women.
They probably thought there was no threat.