Whitney had her own potentially fatal plan B, thought up on the spot and inherently flawed. At the moment her major concern was getting away from HYDRA so that was what what her plan focused on. Options were limited and she was adaptable and so she took this opportunity as her enemies argued to inch away. Not far, half a foot away, to the low brick roof guard separating the edge of the building from the air beyond and the streets below.
"Arguing over me?" she interrupted before they had to resort to rock, paper, scissors to decide who would have the honor of fighting her first. "Well I just feel like the belle of the ball. Sorry, darlings, dance card's full." With that farewell she tipped over the side of the building and began to fall, away from HYDRA and its snipers and away- for the moment- from Iron Man. That wouldn't last long, of course he would catch her. This was how they functioned.
Granted it was putting a lot of faith in someone she'd tortured and tried to kill, but historically there was more reason to expect rescue than to suffer otherwise. Maybe one day he'd let her fall and she'd learn her lesson and she wouldn't take the leap. Tonight she did, confident that however this all ended she'd still won.