Re-evaluating My Thriller

I've had some thoughts as to how to go about making/structuring my thriller opening, the rough cut at least.

ORIGINALLY:

• It would be about a chemistry explosion from an experiment
• There would be fading out to white where the credits would appear
• It would be from the point of view of one of the characters in the film
• The structure of the film opening would be all post-explosion with the enigma of "What happened?"

AND NOW MY THOUGHTS ARE:

• Chemical explosion idea still applies
• I could use a pan shot of the room post-explosion in the beginning
• Use an effect to make it look like everything has been rewinded to how it all started
• BUT I asked myself, where would the enigma go? Questions have to formulate or else it would be a poorly thought out thriller as I've been told by my audience research.
• Also, if I were to change it, that would require extra work, which I'm willing to do, but I have to be conscious of my other courses as well.

I plan to discuss these thoughts with my teacher.