The suit she was wearing in those photos looks like it has a button-front top. She probably unbuttoned it and there was her hidden shirt. Take a look at the shot of her being rushed back up the steps, looks like there is a lighter color on her front, perhaps a shirt under the suit top?
All I can say is, she sure covered it up on her way out.
Missing the chance to get her chest on TV. Wasn't that the point?
Goodness, the speech is over already. Clinton would just be warming up by now.