The title comes from the chemistry Michael uses to melt the barrier. He acquires two specific chemicals—phosphoric acid and an herbicide—which he disguises as toothpaste and cleaning supplies. To anyone else, they look like harmless liquids, but when combined, they create a corrosive compound Michael calls "Cute Poison" (a mnemonic for the chemical formula PO4cap P cap O sub 4
In the fourth episode of Prison Break , titled Michael Scofield is racing against a ticking clock to finish the most dangerous part of his escape route: a hole through a thick concrete wall in his cell. Cute PoisonPrison Break : Season 1 Episode 4
By the end of the night, Michael uses the "Cute Poison" to corrode the back of a metal grate, finally breaking through the wall and gaining access to the maintenance tunnels. The episode ends with Michael peering into the darkness of the prison’s inner workings, knowing he has finally opened the door to the outside world. The title comes from the chemistry Michael uses