Now totally mindfugged!
I don't think Dr Wells is Man in Yellow aka Reverse Flash leh...
Yet they show ending until like that like so much spoiler...

I thought Reverse Flash is someone named Eobard Thawne which sounds like Detective Eddie Thawne leh... That's why Yellow Man didn't kill Eddie...
I think Yellow Man and Flash both travelled back in time when Barry's mum was killed but Yellow Man won... Either Flash got killed during that night or he MIA after that, that's why Dr Wells "future" newsletter says The Flash went missing cos he went back in time and didn't manage to come back.