Alchemical wake-up salve Mordecai claimed to be brewing as cover for the real expulsion potion.
On the replay, Mordecai announces to Rosetta that he is going to pull Carl out using a Shock Wake salve, adjusted to work on a non-corporeal form — a plausible plan, since Carl's split self was translucent and intangible.
It was a lie for the benefit of the illegal watchers. Baroness Victory explains that had a genuine wake-up salve been applied at the same instant as Commander Stockade's drag spell, Carl would likely have died with his soul ripped in two. What Mordecai actually brewed was something to violently expel the Shi Maria presence instead, and Stockade's cackling stopped when it hit.
A salve applied directly to the chest, here modified to affect a non-corporeal target.
The decoy potion Mordecai named aloud to mislead the eavesdroppers.