Your dream contains several significant symbols and themes that can be interpreted in various ways. Here are some insights:

1. Feeling Trapped: Being locked inside a big home suggests feelings of confinement or restriction in your waking life. This might relate to your personal circumstances, relationships, or responsibilities that are making you feel trapped.
2. Threats and Safety: The presence of an external threat implies that you may be dealing with anxiety or fear about something in your life. This could be a situation you feel unprepared for or pressures from outside influences that you are trying to shield yourself from.
3. Giants: The giants, especially resembling characters from "Attack on Titan," symbolize overwhelming challenges or fears that seem larger than life. They may represent obstacles you perceive as insurmountable or feelings of being threatened by situations that feel out of your control.
4. Friends and Choices: Your friends buying drugs could indicate a sense of disconnection or concern for those around you. Their actions may reflect your worries about their choices or how those choices affect your relationship with them.
5. Hiding and Escaping: Your actions of hiding and escaping suggest a desire to avoid confrontation or difficult situations. This might indicate a tendency to flee from problems rather than face them head-on.
6. Complex Relationships: The girl suggesting a relationship involving multiple people indicates feelings of confusion or conflict regarding intimacy and relationships. This might reflect your uncertainties about romantic situations and the dynamics involved.
7. Police and Consequences: The appearance of police suggests a fear of repercussions or being held accountable for your actions or the actions of those around you. This can relate to feelings of guilt or anxiety about being judged.
8. Running Away: Your decision to leave others behind and secure the exit may indicate a desire for independence or an instinct to prioritize your own safety and well-being over group dynamics.

Overall, your dream reveals a complex interplay of emotions, including fear, anxiety, and a struggle with relationships. It may be beneficial to reflect on these feelings in your waking life and consider what changes you might want to make to alleviate these anxieties. Engaging in open conversations with your friends or addressing any unresolved issues could also provide a sense of relief.