While suppressors do not make the weapon quiet, the firearm could be outfitted with subsonic ammunition which by itself is very nearly silent[1] even with larger rifle calibers[2]. Though to be fair the ballistics on subsonic ammunition doesn't even compare to supersonic ammunition which is why they see little practical use. But for a 007 type character who normally engages in very close range that should make complete sense.
[1] - https://www.youtube.com/watch?v=0fb8CLXll9I
[2] - https://www.youtube.com/watch?v=tTdMr8tdL4I