From The Mill on the Floss:
Day break came and the reddening eastern light, while her past life was grasping her in this way, with that tightening clutch which comes in the last moments of possible rescue. She could see Stephen now lying on the deck still fast asleep, and with the sight of him there came a wave of anguish that found its way in a long-suppressed sob. The worst bitterness of parting—the thought that urged the sharpest inward cry for help--was the pain it must give to him. But surmounting everything was the horror at her own possible failure, the dread lest her conscience should be benumbed again, and not rise to energy till it was too late. Too late! it was too late already not to have caused misery; too late for everything, perhaps, but to rush away from the last act of baseness,—the tasting of joys that were wrung from crushed hearts.
What does the part in bold mean? Is it some kind of sarcasm?