[General] Past in the Future

[EnglishLearner007]

Time line  -------------------------------------------->
                     Now              A         B

Assuming A and B are events in the future that hold some significance. Now assume that someone is fearful about event B and is discussing it with me. Would it be right to speak something like below?

Don't worry about event B, because even before it could cause any harm, event A will have triggered and prevented event B to occur in the first place.
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Also, please help me to figure out which grammar construct does this situation belong to?

 

[GoesStation]

Your choices of tense are correct. The sentence falls apart a bit at the end, though. I'd write Don't worry about event B, because even before it could cause any harm, event A will have triggered and prevented event B from occuring in the first place.