Change the future.
For the future too will eventually become the past.
The future also has the potential for a second chance—
Professor Moriarty's voice was as if laced with a bewitching charm, "Even if you have no regrets now... are you so certain the future will be the same?
"As I've said—necessary evils, deaths that come too soon. If the advance time is infinitely reduced, then it essentially amounts to having done nothing; and if the time of rewind is infinitesimally short, it also means that nothing has been lost.
"All it takes is for time to be rewound just in time for regret. Then no tragedy would ever occur.
"It's like those mortals buying insurance. Insurance can't prevent accidents from happening, it can only reduce the loss. Because they can't stop things that have happened from changing, nor can they ensure that something will definitely not happen in the future... but we can.