Give one, take more
White's chain encloses a two-point eye space, and those two points are its whole life story. The throw-in (扑) plays into that space anyway: your stone sits on one liberty, White must capture it, and the capturing stone fills the remaining point itself — the two-space eye is spent, leaving a single one-point eye at best. The mistake is filling the space from outside first: White simply rounds off the eye and loses nothing. Throw-ins like this decide yose races everywhere — one sacrificed stone, one whole point swung.