Constantine is reading the writing on the floor. Normally people read the writing on the wall, but Constantine has to work with what he's got, and he gets writing on the floor a lot more often than not.
Thea is worried about what's going down, which is rather nice if we've read the situation right up to now. Of course, she's kind of in the same boat as Sara. Maybe Constantine can do a little magic on her, as well.
Felicity: What's going on? Ray? Ray: Oliver Queen is the Arrow. Felicity: What? Ray: I have a 140 IQ and three PhDs, but it's pretty hard to insult my intelligence, but I'm pretty sure you just did. It all makes sense now. Your, ah, sudden disappearances, your apprehension of helping me with my mission. You've been working with the Arrow this whole time.