Dreams involving mental hospitals often symbolize feelings of being overwhelmed, feelings of loss, or facing unresolved emotional issues. In your dream, the death of your friend and the involvement of the person who killed her suggests that you may be grappling with feelings of betrayal, guilt, or unresolved grief.

Exploring the hospital could indicate a quest for understanding or healing, reflecting your internal struggle with these emotions. The encounter with the person who caused your friend's death might represent your confrontation with painful memories or unresolved feelings regarding that situation. The silence shared with him could symbolize the weight of unspoken words or unresolved conflicts.

The therapist's encouragement to jump from wall to wall suggests a push towards taking risks or confronting fears. Walls in dreams often represent barriers or challenges you feel are in your way, and the act of jumping could symbolize a desire for freedom or escape from those constraints. Your fear of jumping might reflect anxiety about taking bold steps in your life or facing difficult emotions.

Overall, this dream seems to highlight your journey through grief and the challenges of processing complex emotions. It might be helpful to talk about these feelings with someone you trust or a professional who can support you in navigating your grief and the associated feelings of confusion or betrayal.