Nancy and Si have been at each others’ throats for much of their time together, but here for the first time we see the mask slipping and Nancy showing that she really does care about Si, and not just because the kid’s a quantum oddity that needs an eye kept on. Of course, from Si’s perspective, this unexpected care and attention just underscores how brittle she feels right now, so it’s understandable that she is resentful of her aid rather than grateful.