Nd2 dxe4 4. Nxe4 Nd7 5. Bc4 Ngf6 6. Nxd7 Nbxd7 16. My guess is, it's a quiet position in a solid opening, and neither player bothered to look.
Chess is a tense game.
This tension may make you want to believe things that aren't really true, and comfort yourself with things that mean you don't have to think too hard any more. Black has a hopeless, passive position, just as he has had for the last umpteen moves. Petrosian just went 1. Kg7 discovered check , winning the rook. Kg5 Ke8 White resigns , unable to catch the f-pawn.