The Me’am Loez suggests that Achashverosh would be likely to change his mind if he were to see Vashti again. As noted last week, this would wreck havoc on Memuchan’s plan to control the king. The Vilna Gaon adds that Memuchan is suggesting the king never even give Vashti a second chance to appear. Rashi points out that this is clear indication that Memuchan is hinting to the killing of Vashti (cf. Midrash, Esther Rabbah 4:9)1. Otherwise, how else could one guarantee that the king will never see her again? Since her explicit punishment is not mentioned in the text, it is a matter of discussion amongst the commentators. Most agree that she was killed. Some say she was banished or imprisoned. Rabbi Avraham Chadida writes that she was merely divorced.
1The phrase that the Midrash ascribes to Memuchan is that he wants to put Vashti’s “head on a diskus.” A “diskus” is either a plate or, according to Torah Temimah, a decapitation device. Incidentally, the phrase “rosha badiskus” is the exact gematria of 748, the same as mash’chis, destruction.