UrsusArctos: The penny drops for Rei, she's the vessel of Lilith's soul just like Kaworu is the vessel of Adam's and she can put up an A.T. Field to rival his any day. Too late to be useful against any of the other Angels; at least it served its purpose here.
dzzthink: Since Rei is still relatively loyal to Gendo at this point, she was probably ordered to go there by Gendo. Her A.T. Field might have been necessary to neutralize Kaworu to some degree.
UrsusArctos: An interesting idea, but I doubt it. First, this Rei has started to question her own existence and her loyalty to Gendo is clearly wavering at this point. Second, Gendo is highly protective of Rei and wouldn't want to her to be hurt or killed by Kaworu and Eva-02, especially since there's no evidence he knows that she can generate an A.T. Field of comparable power to Kaworu's at this point. If Gendo knew it, his conversation with Fuyutsuki at the start of the whole uproar would've been very different.
