The Green Lantern Corps actually operated on a system of authority. Every Green Lantern recognized by the Corps could receive a token of that authority—the Green Lantern ring.
But there was a threshold for using that token of authority. You had to possess tremendous willpower to operate the Green Lantern ring and Green Lantern energy. In other words, not just anyone who picked up a Green Lantern ring could use it.
Generally speaking, even if a Green Lantern lost their Green Lantern ring, it would not cause too much trouble, because whoever found it would have no way to use it. They would lack the willpower needed to operate the ring and the energy within it.
But clearly, the current situation was an exception, and to explain it, one had to start with how the Green Lantern ring worked.
For a Green Lantern to use the ring and its energy, he had to use his own willpower to activate it. After sending the command requesting its use, the Green Lantern ring would determine whether that willpower was sufficient to drive it. If it was, the ring would begin operating, transmitting energy to the Green Lantern.
What had happened was that when Hal activated Green Lantern energy, he had intended to teleport. He sent that command to the Green Lantern ring, and after checking, the ring found that he had the authority to use it and its energy, so it began operating.
The energy had already been sent out, covering Hal's entire palm and half his arm, when Aisha bit down on him.
The reason Green Lanterns feared Yellow Lanterns was that Parallax had originally been sealed inside their Central Power Battery. Now, however, Parallax had not only escaped, but had also become a human little girl. Logically, Green Lantern energy