I am as confused as others on this one. Flash backs are typically black background instead of the usual white. This background is brown. I don't think it's a flashback but it's not the present either. The last we saw Ji-ho with white background, she was getting a good slap and remember her body is frail after her accident. She could be unconscious after hitting the ground. Maybe even in the hospital. What we are seeing is probably an hallucination brought on by the trauma. If so, we are seeing a mix of memories and dreams for our own interpretation.