[aohige]

Originally Posted by Revolutionist

My question is, why does Euphie go psycho and start murdering all those people? O_o

Here's the short summary of what happened.

Spoiler:

Euhpie says she'll step down from royal family, for Nanaly's sake, and Lulu decides to ally with her. They shake hands.

Lulu tells her he can command anyone to do anything... for example, if I order you to kill Japanese...

At this point, the geass goes out of control, and she gets geassed.

At first she tries to struggle against the command, saying "I don't want to kill...!"
But soon Geass brainwash takes over, and goes merrily off to killing spree.
She first shoots a representative, shoots Dalton who gets in her way, and orders the troops to massacre.

Her geass probably won't stop until every Japanese is dead, or she's dead.

At the end of the episode, Lulu tells the OoBK that Euphemia is the enemy, and orders them to kill her.