OOC: You are correct, Set. You can use the rule called "extra effort" to temporarily pick up a power stunt. Spending the hero point keeps you from becoming fatigued afterwards.
IC:
ORCA begins using his sonic powers to create a tunnel through the rubble. While he is working on it, Shade moves near the entrance to the mine shaft, trying to stay out of ORCA's way and phases into the ground.
"Where's the kid going?" Tyke asks no one in particular.
Spyder keeps watch around the area, expecting some sort of further attack from whoever might be inside the mine.
Shade makes his way through the ground, occassionally coming up and trying to find a clear area. After several minutes, he comes up out of the ground into a small pocket that is clear of rubble. In the small space is a wall of some sort. Looking closer, it appears to be made of metal. Shade is unsuccessful in attempting to pass through it in his incorporeal state. Some sort of force field is protecting it.
By the time Shade has reached the metal wall, ORCA has tunneled through to some sort of solid barrier that he cannot tunnel through. The tunnel he created is more than 100 feet long, and disappears into the darkness of the collapsed mine.
OOC: Okay, Shade is in a pocket that is free of rubble, with earth and stone on three sides and a metal wall protected with a force field on the fourth side. His rubble free pocket is not part of the tunnel created by ORCA. ORCA tunneled through for about 30 seconds before reaching an impassable barrier, the same metal wall that Shade has discovered, just a different location along the wall.