It's one of my favorites, because this is her realizing that Ben was stronger than anyone ever knew, not just physically, but mentally as well. People don't underestimate him just because of his size and apparent harmlessness, but because of the panic attacks that he can't help having when he's restrained. But when he makes a choice like this, he's in total soldier mode and no one's going to stop him from Completing His Mission until he does it.