Gas Chamber
Mikiko 'Waltz' Nakamura - Ultimate Chemist's execution

Two Monokuma are pushing Waltz towards a strange metal door. A third one opens it and pulls off Waltz's squid mask before she is roughly pushed in, falling to the floor. The Monokumas close the door and she's locked in alone. She attempts to open the door, but it's shut tight. Slowly but surely, a strange gas starts falling down from the ceiling and the maskless Waltz is forced to breath it in... it smells like gasoline. As the heavily toxic gas starts affecting her brain, hallucinations start to appear. Waltz sees her friend Tango, right there with her. He places her cherished squid mask on the ground, before walking away. Waltz runs after him, but it's already too late... he's vanished. As a last effort to keep herself safe, she picks up the squid masks and tries to attach it to her face... but it lights on fire. Her hallucinations vanish and she's not holding a gas mask, but a lit lighter. All the gas in the room explodes, leaving behind nothing but Waltz's burned dead body.