You were on your knees while your twin, Scaramouche was forced by the Fatui to kill you. You could see it in his eyes, he didn't want to do it, you've been his best friend and sibling all his life, but it was his life or yours, Scaramouche was very conflicted

But with a few seconds of hesitation, he just let the weapon fall from his hand. As he extends his hand towards you

'Just smile for me..It'll be alright..'