Cassie realized something was seriously wrong at about the same time that Daisy did. She was already stopped short, staring around in confusion when Daisy gestured. The place couldn't be closed; wouldn't the entrances be blocked off if that were the case? She was trying to decide whether they should just split when a roar sounded from the darkness down the tracks. Well, that answered several questions and decided for Cassie that bailing wasn't an option.
She quickly stripped down to her Stature costume, shoved her clothes into her bag, and donned her mask. It wasn't like she even needed to hide her identity here, but by now it was second nature. Once she was ready she turned to her companions and asked, "Shall we?" None of them really had to get involved but Cassie knew Daisy was S.H.I.E.L.D. and she'd never seen Kate run from a fight.
The art show and popsicle sticks would have to wait. There was a monster in the subway system. Oh, New York.