In Hesiod’s Pandora story, evils escaped first from the container.
In Works and Days, Pandora removes the lid from the covered container, and the contents fly out into the world. Hesiod describes diseases and countless other evils spreading among human beings, where they had previously been kept away. The narrative does not present the container as a literal modern box; the Greek word is pithos, a large storage jar.
Hope remains inside after Pandora replaces the lid. That ending has generated centuries of debate because readers disagree about whether hope is a blessing retained for humanity or another force withheld from it. The poem itself does not settle the later philosophical interpretations.
The popular phrase “Pandora’s box” comes from a later translation tradition. The sequence of evils escaping first, followed by hope remaining inside, belongs to the ancient literary account.