Joss Whedon, who directed and co-wrote Avengers,has a long history working with female-centric franchises: Buffy the Vampire Slayer (both the film and the TV series), Dollhouse, and a much-lauded 2008 run writing Marvel's own X-Men. In accordance with Whedon's M.O., this version of the Black Widow (aka: Natasha Romanoff) is more than a token female team mate in constant need of rescuing. She's a domineering spy/assassin who makes equal use of her skill and physical beauty to manipulate her targets like man-clay.
When we first meet her, Romanoff is tied to a chair, clad in a black cocktail dress, being violently interrogated by a trio of gangsters. Confident that they are in complete control of the situation, the leader of the three foolishly reveals his master plan before the Black Widow reveals her true skill, subduing all three men in an impressive display of acrobatic ass-kicking. Her perceived vulnerability is a weapon that Whedon has her use multiple times throughout the movie.
But her strategy is always predicated on her having the upper hand. The gangsters are human, easily willed by her charms. But during an attack on the heli-carrier in the second act, Romanoff becomes trapped in the lower engine decks with Bruce Banner, who loses control and becomes his unstoppable raging alter-ego, the Hulk. Her attempts to reason with him fail, and soon she is running for her life through the bowels of the ship, chased by the unthinking green mass of rage. The Hulk swats her against the wall like a mere insect before the Norse God of Thunder, Thor, intervenes. When next we see her, the Black Widow is cowering in the corner. The look on her face is that of a woman utterly broken. It takes a few moments before she finally responds to her radio summons.
The scene touches effectively on two themes. The first is the trauma suffered by the Black Widow, a woman so accustomed to being in control who suddenly finds herself dominated by an unstoppable male force (one from which she had to be rescued by another man). Finding a way to assert yourself against someone more physically powerful is a challenge that persists in women's struggle for equality, fictional or otherwise. That challenge, of course, is more easily addressed when you have super powers and can reduce your opponent to ashes, but the Black Widow's helpless encounter with the Hulk more closely reflects that problem as it exists in the real world.
The second taps into the deeper issue, rarely addressed in super hero films or comics (Garth Ennis's super-team satire,The Boys, comes to mind), of what it would be like, as the female minority, to be constantly surrounded by men who could overpower you physically. The Hulk, a supposed ally who simply loses control, is the perfect embodiment of the unchecked male rage that so often victimizes women.
With a dozen other character arcs to wrap up in the film's two and a half hours, Whedon never addresses the issue again and we're left wondering how the Black Widow was affected by her encounter. It's too bad, because in a movie fraught with cartoonish destruction, it's the one moment where the audience actually sees some real damage.