Revealing mistake: During the fight between Bond and Peter Franks in the elevator, if you watch carefully when Bond hits Franks' wrist with the door while he is holding the glass shard, Franks drop the glass shard before his wrist gets hit a second time.
Revealing mistake: When Bert Saxby is shot there is no hole in his shirt, only painted on fake blood.
Revealing mistake: When the row of missiles blow up near the end, not only are the effects bad but the amount of smoke shown is cartoonish and the missiles are still intact afterwards.
Revealing mistake: When Mr Wint puts the scorpion down the back of the doctor's shirt while he is looking at Mr Kidd's wisdom teeth, the scorpion is made of plastic and not a real one.
Revealing mistake: When Mrs Whistler's body is being removed from the canal in Amsterdam, it's clear in the long shot that it is just a dummy.
Revealing mistake: When Bond knocks Blofeld unconscious with a lamp in the fight at the start of the film, look carefully and you can see that Blofeld is already knocked out before the lamp comes into contact with his head.
Revealing mistake: When Bond hoists Mr. Wint overboard with the bomb tied to his coat-tails, Mr. Wint is not Bruce Glover but a stunt double.
Answer: If you mean by hiding - why is he never seen normally - then it's because he is a recluse and doesn't like to be seen in public (like Howard Hughes was). If you mean by hiding - why was he not seen during the movie - then it's because he was being held captive by Blofeld and his minions. Spectre didn't want him out and about ruining their plans.
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