For a moment, Luke was lost for words.
After he pulled Selina into the world of superhumans, he had indeed kept her sheltered.
It was mostly out of guilt.
Being a superhero with Batman was much more dangerous than being a vigilante.
The undead monsters, the test subjects, the Chitauri army today, and the American bigshots who set up traps behind the scenes were all extremely dangerous enemies.
Other superheroes might be killed if they were caught, but if Black Cat fell into someone else's hands, it might be hard for her to die even if she wanted to.
Thus, in many of their previous battles, he had made sure that she didn't run into any danger that was beyond her scope of capability.
However, he was unable to fully protect her today under the crushing pressure of the Chitauri army.
Selina finally showed her determination.
This was the real Selina.