In the film The Maze Runner, at the near end when Thomas, Teresa, Minho, Newt and Chuck as well as the rest of the Gladers who decided to stand for the escape and fight their way through the Grievers to get out.
When Gally tries to put up an 'offering' and tie Thomas and Teresa to poles just outside and in front of the Door, a little something happens to cause a bit of chaos.
Thomas and Teresa convinces other Gladers to join the fight and get out. Though only have a few spears, namely Thomas, Minho and Newt.
There is no evidence that suggests that they turned around to go to the armoury in the Glade to get weapons. The majority of the escapees went into the maze unarmed.
When you look at a further scene, when they turn a corner in the maze to get to the exit, they are all armed with spears.
Where did the other gladers get the spears from and when?