"Rainbow!" Twilight pried Rainbow's hooves off her, "If we broke them out, Faust would only come after all of you again, and next time she mightn't try to take any of you alive!" Twilight gave Rainbow a moment to let that sink in. "While our friends are in her possession, she has no reason to kill them, or come after the rest of us! And if we rescue them, and end up with no way to stop Faust..." Twilight didn't finish, letting Rainbow's imagination do the work of filling in the gaps. It clearly worked too as Rainbow released her and sank to the ground.