A blade arrived in the envelope—could the implication be any clearer?
Someone was obviously threatening him!
Previously, afraid that An Hao would worry, he had secretly tipped the blade out and casually put it in his pocket.
Since there was a sentinel on duty, he couldn't just discard the blade on the ground where it could be found. If the sentinel picked it up and gave it to him, An Hao would naturally see it and would surely be worried.
He didn't want An Hao to worry, so he quietly slipped the blade into his own pocket.
Yet, after he walked out of the compound, he somehow forgot about it, and the blade had remained in his pocket ever since.
Qin Jian glanced at the coat rack; his military uniform that hung there was gone, certainly taken by An Hao to wash.
She must have found something in his pocket and taken it out. He just didn't know whether she paid any attention to the blade or if she would ask about it.