Sun Hao is responsible for the security of the train station area, not the area of Old Sir He's house, but He Caixia doesn't know that, especially since she really did climb the wall to get in.
When Su Wensong caught her with a uniformed officer, He Caixia was genuinely frightened.
She quickly explained her relationship with Old Sir He.
Having been warned in advance by Su Wensong, Sun Hao naturally didn't let her go, asking for proof or to contact Old Sir He.
What evidence could He Caixia provide? She hadn't been in touch with Old Sir He for a long time; it was only because her sister told her that Old Sir He had a very capable apprentice, and this apprentice could solve her husband's work problem, that she wanted to reconnect with the old man.
As for contacting Old Sir He, it was impossible.
She didn't even know where Old Sir He was, so how could she contact him?
Sun Hao saw her reaction and didn't listen to her explanation, directly taking her to the police station.