"Real Dreamland" hypothesis had answered many of Wang Yunxiao's doubts about the Outer Dimensions.
First, it wasn't that Nurse Liu liked to talk in riddles, but that they lacked the mental capacity to accept the truth.
The more ignorant a person is, the more fearless they become.
Normal people know that cars on the street are owned and that stealing them is against the law.
However, not everyone on the street is normal; some might think your car is unwanted and could simply drag it away to sell as scrap metal on the spot.
Second, to bring back items or other things from the Outer Dimension to the Real World, specific conditions needed to be met.
Chen Yan hadn't described it accurately—it wasn't contamination, Wang Yunxiao felt it was more apt to describe it as "legendary presence."
Everyone knew that Nurse Liu had a handgun and had even fired it in school. Therefore, in everyone's consciousness, the gun "existed."
Existence justifies itself.