Why does it seem like the MC is talking fondly of the scumbag Hero who not only abused him but also abused everyone else? Especially since we know that him being a Hero is not some divine pre-ordained thing but just a government controlled title.
MC seems to be turning from a strategic thinker to an adrenaline battle junkie here, albeit just for a short bit, with a general excuse of "Oh it's just like my alchemical experiments".
Then again, considering how he made Allen drink all his home made potions, he might be subconsciously be looking at Allen as his human testing guinea pig and part of him has started to turn into full Hojo from Shinra.