If he chooses to kill her & save himself, he's punished for his selfishness.

The wires around the woman become highly electrified. This doesn't shock her, because the wires are more conductive than flesh & she's not grounded anyway, but the resistive heating does superheat them, leaving her with criss-crossing burn marks all over her body. After a second or two, the wires sag & break, & she falls to the floor.

Jigsaw tells her that the man wanted to kill her, thus proving you can't rely on the kindness of others. Then a door opens up for her & she walks home injured & naked, but alive.

Meanwhile, the man has been paralyzed by a poison needle hidden behind the "save yourself" button. He can't move, but he can still breathe & still feel.

Jigsaw tells him he'll "suffer for his psychopathy in a tomb of his own greed". Then, a machine drops lit tinder atop him, lighting his suit ablaze.