Your dream is rich with symbolism and emotions, reflecting various aspects of your life, relationships, and internal struggles. Here's a breakdown of some key elements:

1. School Setting: The school could symbolize a learning phase in your life or a time of personal growth. Being surrounded by familiar people suggests a desire for connection or comfort in your current environment.
2. Bakery and Sweet Tooth: The bakery represents temptation and desires. Your sweet tooth may indicate that you seek pleasure or satisfaction in life, but the choice of options could also signify overwhelming choices or feelings of indulgence that might lead to anxiety.
3. Flirting and Trust: The interaction with the bakery owner suggests a mix of attraction and trust. However, the age gap and subsequent anxiety signal an awareness of boundaries and the potential for inappropriate dynamics in relationships.
4. Anxiety and Running: The sense of anxiety and the act of running away reflects your instinct to escape from a situation that feels threatening or uncomfortable. This could relate to a fear or concern in your waking life that you are trying to avoid.
5. Brother's Inaction: Your brother’s presence and lack of action may symbolize feelings of disappointment or a sense of vulnerability. It could also point to a desire for protection that you feel is absent in your life.
6. Locked Doors: The repetitive act of locking doors that keep opening indicates a struggle to feel secure. This can represent feelings of powerlessness or a fear of not being able to protect yourself from external threats.
7. Confrontation and Resolution: The climax of the dream, where you confront the threat using his childhood trauma, suggests a desire for empowerment and the need to face your fears. It indicates that you are seeking closure or a way to overcome past traumas, either your own or those of others.
8. Trembling and Paranoia: Even after the confrontation, the feeling of trembling and paranoia points to lingering effects of trauma or anxiety. It can signify that even after facing fears, the emotional aftermath can still be unsettling.

Overall, this dream reflects a complex interplay of desire, fear, and the need for safety and empowerment. It may be beneficial to explore any real-life situations that resonate with these themes. Understanding your feelings and seeking support from trusted individuals can help you navigate these emotions more effectively.