On the way there, Beichuan Si told Shen Gu Mirai about the Voodoo Doll.
But to be fair, Beichuan Si had never used the doll himself, so he did not know the exact effect of its substitution ability; hence, he only shared the general effects with Shen Gu Mirai.
After all, if Shen Gu Mirai thought having the substitute doll would allow her to lower her guard, that could actually lead to bigger problems.
Thus, Beichuan Si did not exaggerate the doll's use and explained it in a straightforward manner.
Upon learning of the Voodoo Doll's significance, Shen Gu Mirai blushed and placed it in her shoulder bag.
She didn't speak of returning the doll to Beichuan Si.
Because she knew for certain that Beichuan Si would not take the Voodoo Doll back.
Moreover, Shen Gu Mirai's self-assessment had always been accurate.
"Helping Beichuan Si as much as possible without causing him any trouble."
That was Shen Gu Mirai's self-placement.
She had always been sharp-witted.
