Most of the Keepers at the Gathering think Minho's proposal is absolutely ridiculous, although some of them seem to consider it.
While Minho is defending his position, Gally rudely interrupts him (again) and we discover that the reason he was stung was because he broke the same rule Thomas did. Hypocrisy, Gally is thy name.
Anyway, Minho continues telling everyone all of the brave, amazing things Thomas did out in the Maze, and at the same time insults Gally by saying that he's just a coward who couldn't even consider being a Runner. This, apparently, is the last straw for Gally, and he threatens to break Minho's neck.
Minho takes Gally down, humiliating him further.
Gally backs out of the room and threatens everyone (but particularly Thomas), and then disappears.