Now This Post Won't Make Since If You Haven't Watched Dark Knight Rises in that case go watch it NOW!!!!
So In last Nights Episode of the Flash Escape From Earth 2 it starts with zoom running through the city wanting them to give Dr.Wells up. He wants Wells so badly and wants to make a point. So he burns the letters Bring Me Wells.
Now it might not have been on purpose but this reminds a lot of Batman where, He burns the bat signal into a bridge so he gets the whole cities attention to make sure they know they he isn't gone.
Now like I said It could just be a coincidence but I think they knew.