Zhao Ling'er didn't wait for a single second after she entered and placed a spatial boundary surrounding the room using her spiritual power. The boundary couldn't be broken into unless the attacker was more powerful and had more exquisite control of the power compared to Zhao Ling'er.
As there was no one stronger than Zhao Ling'er in the whole household other than Zhang Jian, it was practically indestructible and could exist indefinitely until Zhao Ling'er decided that it was no longer needed.
The boundary even separated all noise from the outside and vice versa. It was like the room was no longer in the same space as the rest of the house. This was exactly what she needed to carry out the next part of the plan.
