Lu Xiaodao only told us that he eavesdropped on the formula after the experiment was a success.
He was able to leap up a tree, even when the ground beneath him suddenly gave way, demonstrating his light-footed skills. After Meng Qingyu brought them out, she arranged for them to stay in a villa.
There was a month's preparation period for this operation. During that month, using his wall-climbing abilities, he eavesdropped on a phone call between Meng Qingyu and someone in the organization.
On the call, she said there was no antidote outside; the materials to make it were on the island.
Because the poison she used to threaten Lu Xiaodao and the others came from a venomous insect on the island.
And a few plants on the island happened to counteract this insect's poison. Perhaps during the call, she was feeling smug, having deceived a bunch of fools to work for her, knowing that regardless of whether they make it out, they'd end up dead.
