Squid Game Ending Confusion

Hi I recently watched last episode , where 001 and 456 were discussing the attack strategy of O team whether to attack first or not , Suddenly the light flashes start and they start narration and all the actions are going in the way they were expecting and story gets very fast and I am now confused are they in the imagination or it was the ending? , Or in the next season I think it will start when the lights out.