Black has now moved this same piece three times. White has gained two tempi for free. Two tempi in the first ten moves is good enough to mount an immediate attack against the opposing king. See the games of Paul Morphy for examples.
11. Ra1c1 Nc6xe5
Black is behind in development, and now trades off one of his developed pieces. This effectively hands White another tempo, as if White could make three moves in a row and Black were frozen.
Retaking with the pawn here, instead of the bishop, forces Black to retreat his knight. The knight was the only piece defending the king. White now has sufficient force to directly assault the Black king position, with a probable bishop x h7 imminent, queen sliding over to g4 or h5 at an appropriate moment, etc. This is a standard attack against a castled king --memorize it!
12... Nf6d7 13. Nd2f3
With the knight poised to jump to g5, further hammering the Black king position, Black can resign here.
... g6 or h6 was imperative, to stop White's next move. White still has more than enough initiative to continue the attack though.
If ... KxBh7, then Ng5+, K anywhere; Qd3, Qg4, or Qh5 and it's doom. 1 - 0