Sakuya may not have progressed that far yet to use the "space" aspect yet or instant knifing could also be a tell of her manipulating space.
Her ability to move, breath and interact with things while within stopped time is where her manipulation of space comes from. ZUN realized that she couldn't do much if all she could do is stop time, she'd be frozen too, so he errated it.
My understanding may be only roughly, but...You understand my ability?It's "the power to manipulate time and space", isn't it?Stop joking...Well then,Anyway, just sit back and watch.That's because,Onee-sama will surely meet my expectations.That's because,she's Onee-sama after all.she's Onee-sama after all.let's get this over with, shall we?
