plot explanation - No "spider-sense tingling"?

In Spider-Man 2 (2004) there are a number of scenes where Peter Parker exits and comes back as Spider-Man only after he witnesses something wrong (even if he is in the vicinity of the occurring crime).

Like, in the scene where Doctor Octavius' fusion reactor is about to explode. They make no mention of Spidey's Spider-Sense .

And in the bank-job scene, Peter Parker is right there with Aunt May opening up a "super-saver account" and yet he does not "sense" that Doc Ock is about to pull a job.

So, I ask you... What is up with that ?

Answer

During Spider-Man 2, Parker goes through a puberty, if you will, regarding his identity and what it really means for his life as a whole.

Due to all the stress of school, MJ seeing what seems to be the perfect guy for her, and being Spider-Man, he decided to try to give up being Spider-Man when his powers start to diminish as a result of all these burdens upon him and his desire to just be normal.

Due to this, it would indicate that his Spider-Sense would also be not working just like his web and his wall-climbing abilities; hence him not being able to predict actions and crimes as well as he used to.

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As far as the bank job specifically, I believe it has been mentioned in the comics that because Doc Ock's tentacles are mechanical it causes them to not be picked up by his senses very well, hence Ock being able to get the drop on him in the bank as well as during their fights (I cannot find any sources for this at this time, however).

During the first fusion reactor scene (which is the one I assume you mention), this might be due to his powers dwindling that he does not sense the explosion or because he is too distracted by being at a demonstration from his idol that this gets in the way as well; it is made quite clear during this film that his emotions control his powers. Another explanation is obviously a plot hole or even that because he was surrounded by so many people, by the time he could react without leaving to put his suit on, he would expose his identity.