What does Mark 5:10 mean?

Jesus and the disciples have crossed the Sea of Galilee to the eastern shore, near the southern portion of our modern-day Golan Heights. As soon as Jesus steps out of the boat, a man possessed by a "legion" of demons meets Him and tries to manipulate Him into swearing He will not hurt them (Mark 5:7).

It's not exactly clear why the demons don't want to be sent out of the country. In Daniel 10, an angel mentions a battle with the Prince of Persia—presumably a demon who had some authority over Persia in the time of King Cyrus. And Satan has been called the "ruler of this world" (John 12:31). Matthew 12:43–45 suggests that demons don't like to live in uninhabited places. But the Bible doesn't specifically say that human-occupied areas are sectioned off to be harassed by specific demons.

The parallel passages in Matthew and Luke shed light on the demon's meaning. In Matthew 8:29, the demons ask Jesus, "Have you come here to torment us before the time?" Luke 8:31 says, "And they begged [Jesus] not to command them to depart into the abyss." The abyss is a place of torment currently dedicated to demons, imprisoned for their crimes. Jude 1:6 says, "And the angels who did not stay within their own position of authority, but left their proper dwelling, he has kept in eternal chains under gloomy darkness until the judgment of the great day." These "angels" are thought to be the demons who mated with human women to create the Nephilim in Genesis 6:1–4. During the Tribulation, these demons—described as a kind of locust— will be released to torture the Antichrist's followers for five months (Revelation 9:16). During the Millennial Kingdom, Satan, and presumably all the demons, will be confined to the Abyss for a thousand years (Revelation 20:1–3).

It appears that the legion of demons knows they will one day be sent to torment in the Abyss and are pleading with Jesus that they not be sent early. Comparatively, possessing and drowning a herd of pigs is a good option.