Lu Xingzhi did not want to wake Jiang Yao, so he got up very quietly. His actions were so light that she did not know that he had left. When she opened her eyes, Lu Xingzhi had already returned to the army. It had already been one or two hours since he left.
After Jiang Yao woke up, she thought of Lu Xingzhi's fox-like personality. When she got out of bed, the first thing she did was to look under it to see if the box she had hidden was still safe and sound. When she saw the thread of the box, Jiang Yao was relieved. It seemed like Lu Xingzhi had not seen it or rummaged through it while she was asleep.
He was as impatient as a three-year-old when it came to his birthday present. Therefore, Jiang Yao had been keeping an eye out for him to peek at it. If he had seen it, then there would have been no surprise at all.
She had been folding the paper cranes when Lu Xingzhi arrived the previous night. If she had not acted quickly, he would have seen them.