Arknights: Dark Past

Waking up in a strange bed, our MC travels an alternative world of Terra. One where the Doctor was not a loving commander. Or was he?
"In the path you will be taking, no decision will be easy and not every rout will end in a good way. But continue going forward, your future is yours to make." The Author.

Important note: the story's quality increases a lot in the chapter Broken Hearts and beyond, so only read the previous chapters for context.

(Disclaimer: I took inspiration from the story "Arknights: Correcting The Doctors Evil Deeds" recommend reading it. If similarities are found, please don't scold me.)