In this case, black don't have other answer, because if any white stone manage to connect out, black simply don't have enough eye space.
Making the exchange of / first before yields the same position.
It doesn't really matter which side black captures first, white just makes the throw in and both black chains are under atari again.
In this diagram black can't play to capture at c because it's a snapback, so black captures the other side.
After white throws in again, black is caught in double snapback
Back to the very beginning, in this diagram doesn't work. After to , a and b are miai for black to secure the second eye.
If white plays at c, the same sequence works for black.