Following the first Tosfot Pesachim 2a (1) there is no need for bedika in this case because there is no risk he will eat it, Bedika is a stringency added miderabanan (Chiddushei haRitba explains that Bedika is miderabanan if he already did make a bitul, not before, before it's deorayta. The comment of Rashi is close to this, Bitul or Bedika is deOrayta when it falls in first position. And he writes further that the Rosh says that even before bitul Bedika is miderabanan. Tur OC 436 also rules it's derabanan. The Ran says that chachomim are afraid that some people will not make sincerely the bitul.).
(1) ונראה לר"י דאע"ג דסגי בביטול בעלמא החמירו חכמים לבדוק חמץ ולבערו שלא יבא לאכלו וכן משמע לקמן (דף י:) דבעי רבא ככר בשמי קורה וכו' או דלמא זימנין דנפל ואתי למיכליה
But from the Gemara teku regarding Chamets at the bottom of a well, regarding Chashash perhaps he will go down to fix something, office is not less a Chashash.
But following the end of the Tosfot even if it's miderabanan, from the Gemara regarding Seur, we say that there is no bal yerae and no isur after pesach but he needs to burn it. So, there is a chyuv Bedika even without the risk to eat.
But the Gemara in 6a says that if he leaves the office less than 30 days before Pesach, despite that he will not come back into Pesach, he needs to make Bedika because the mitzvot of Pesach are already relevant. See SA OC 436.1.