This is interesting.
First I was wondering how it could be not lishma, since, did he make the matza intending it for purim? No, he intended it to be sold to someone to eat on pesach while doing the mitzva. So that seems lishmah.
But the teretz is, that he expected them to fall for his extortion, so he was intending it to be thrown out after he told them which one it was.