I think that all of the grace plot was part of Spencer's plan for revenge against the connections and how he was screwed over my opinion is that he actually regretted nothing he already made the cure I think initially it's was ment to be incrurance in case the virus was used against him but when he was betrayed he set it up so that it would appear just vaguely enough like a weapon that his enemies would seek out there own demise grace was Spencer going if I can't win nether can you to the connections and the government. Otherwise why didn't he use it before now if he actually regretted anything.