12.Nd2 c5 (12…Qxg2 13.Ke2!, and Black’s king is walking a tightrope) 13.dxc5? Rd8.
With the hook on h6, the g-file may soon be opened. Since White has not castled yet, he will soon make use of this.
14.Bh6 Bf6 15.Nf4 Ne5 16.Nh5 Kh7 17.Bxg7 Bxg7 18.Rxg7+ Kh8 19.Qc1 Nf3+ 20.Ke2