The reason Bai Meiyue was being this cautious was simple. Before Doomsday started, there were countless people who were affected by the Doomsday virus, and all of them got admitted to the hospital. They were the first batch of zombies that appeared after the apocalypse broke all over the world.
Since that was the case, there was a very good chance that the hospital might have multiple high-ranking zombies. With these mutated zombies along with the ordinary zombies, the amount of risk would certainly get higher.
Bai Meiyue wanted to rush to the hospital, rescue people and collect the crystal nuclei. However, she also understood that there was no point in rushing things. Even if she was in a hurry to return home, she needed to first take care of her safety.