Taking a deep breath and rubbing his hands across his shaven head (he could not stand his hair any other way after prison), he faced Bellatrix once more. She had a point and he did not like it when he could not think logically. Azkaban stripped him of his logic, leaving him with nothing but bitter memories and a sense of failure.
And perhaps the four of them did contribute more. It was not as though the Dark Lord wrote them a 'thank you' note after the break out--he simply expected loyalty and the appreciation they were no longer imprisoned.
"But we are free now and our greatest reward is to finish what he began."