When we consider the biblical source of "gadarene", we find that the dictionary meaning, "unthinking"*, is superficial, if not altogether misleading.

In the bible story, a man possessed by a "legion" of demons approaches Jesus asking him to use his powers to "send us into the swine". Presumably, the "unclean spirits" who possessed the man found their accommodations within their human host somewhat cramped.

Jesus granted the legion what they wished, but then sent their new hosts hurtling over a cliff.

This freed the possessed man and terminated the legion of "unclean spirits" at one and the same time, in a fell swoop [quite literally].

Was this "gadarene rush" to death "unthinking"? Certainly, in the mind of the swine, and also in the mind of the bewildered "unclean spirits". But not in the mind of Jesus, to be sure.

The real meaning of a "gadarene rush" is not what the dictionaries tell us.

It is a fatal stampede, engineered by someone on purpose, not unthinkingly, but shrewdly and purposefully, to purge an evil.

Anyway, that is what I take from the biblical story which follows:

The Gadarene Demoniac Healed
The Gospel according to St. Mark - 5
Mt. 8.28-34 · Lk. 8.26-39

http://www.bartleby.com/108/41/5.html

Now there was there nigh unto the mountains a great herd of swine feeding.

12 And all the devils besought him, saying, Send us into the swine, that we may enter into them.

13 And forthwith Jesus gave them leave. And the unclean spirits went out, and entered into the swine; and the herd ran violently down a steep place into the sea, (they were about two thousand,) and were choked in the sea.

14 And they that fed the swine fled, and told it in the city, and in the country. And they went out to see what it was that was done.

15 And they come to Jesus, and see him that was possessed with the devil, and had the legion, sitting, and clothed, and in his right mind; and they were afraid.

16 And they that saw it told them how it befell to him that was possessed with the devil, and also concerning the swine.

17 And they began to pray him to depart out of their coasts.

18 And when he was come into the ship, he that had been possessed with the devil prayed him that he might be with him.

19 Howbeit Jesus suffered him not, but saith unto him, Go home to thy friends, and tell them how great things the Lord hath done for thee, and hath had compassion on thee.

20 And he departed, and began to publish in Decap'olis how great things Jesus had done for him: and all men did marvel.

* Encarta: gadarene

fast and without thinking: rushing headlong en masse (literary)

Merriam-Webster adds the word "precipitate" which M-W defines thus:

Main Entry: pre·cip·i·tate Function: adjective

1 a : falling, flowing, or rushing with steep descent b : PRECIPITOUS, STEEP
2 : exhibiting violent or unwise speed
- pre·cip·i·tate·ly adverb
- pre·cip·i·tate·ness noun

synonyms PRECIPITATE, HEADLONG, ABRUPT, IMPETUOUS, SUDDEN mean showing undue haste or unexpectedness.

PRECIPITATE stresses lack of due deliberation and implies prematureness of action <the army's precipitate withdrawal>.

HEADLONG stresses rashness and lack of forethought <a headlong flight from arrest>.

ABRUPT stresses curtness and a lack of warning or ceremony <an abrupt refusal>. IMPETUOUS stresses extreme impatience or impulsiveness <an impetuous lover proposing marriage>. SUDDEN stresses unexpectedness and sharpness or violence of action <flew into a sudden rage>.