I believe you're seeing local time on that tweet - it's showing 3:40 PM here. As for him saying he won't drop out, he says a lot of things. I don't think he will, at least voluntarily, but I don't consider a tweet (from the Android) to be good evidence.
On a positive note, Twitter has certainly gotten mighty entertaining these last couple days. I'm not getting much accomplished this weekend. (Yeah, it's old, but I hadn't seen it until today.)