Your dream appears to reflect a mix of your current experiences at school, your feelings about authority figures, and perhaps some underlying anxieties or fears. Here's an interpretation of the key elements:

1. New Chemistry Teacher: The chemistry teacher symbolizes a new authority figure or mentor in your life. The initial perception of him as "cool" and knowledgeable may reflect your hopes for a positive learning environment or a desire for guidance.
2. Exam Preparation and McDonald's: The setting of preparing for an exam indicates stress or pressure related to academic responsibilities. The inclusion of McDonald's suggests a need for comfort or a break amidst this stress.
3. Timer and Fear: The ticking timer represents anxiety about impending challenges or deadlines. The initial fear of an unknown threat could symbolize your worries about the exam or other academic pressures.
4. Electrocution and Death: This shocking event could symbolize fears of failure or the extreme consequences of mistakes, particularly in a high-pressure environment like school. The classmate's death may represent a fear of losing control or the potential for disastrous outcomes in your academic life.
5. Dissolving the Body: The act of trying to "dissolve" a problem may indicate a desire to resolve issues in a drastic or unconventional way. It could also reflect feelings of helplessness when faced with significant challenges.
6. Fire and Destruction: The burning of the building signifies a loss of stability or safety. This could represent your fears about the repercussions of mistakes, whether in academics or social situations.
7. Breaking Bad Reference: The similarity to "Breaking Bad" might indicate that you are processing themes of transformation, moral dilemmas, or the consequences of choices in your life.

Overall, your dream seems to encapsulate a mix of excitement, anxiety, and the desire for control in a new academic environment. It may be helpful to reflect on what specific aspects of school or your current life are causing you stress and consider healthy ways to address these concerns. Remember, it's okay to seek support from friends, teachers, or counselors if you're feeling overwhelmed.