Here's a link to the game Rowson mentions against Yermolinsky. The critical position ("Yermolinsky offered a pawn as bait...") arises on move 18.
It's not spectacular - I would say mundane, but you can't say that when someone beats a top GM in just 24 moves. What Yermolinsky overlooked is a famously missable type of move - a backwards move to a square that was occupied at the start of the variation - but still trivial for a player of his class.
It looks to me like he did not like his position after move 16 and sought these complications partly as a bluff. The computer says Black's position is not all that bad after 16...dxe5 or 18...dxe5, but he will have to either defend a passive position with a weak d-pawn or sacrifice a pawn in a different way.