They watched Rigsy work, only Aderyn and Clara having any idea what the plan was.
Inside the TARDIS, the Doctor didn't have the same hope as them. With no power, the TARDIS interior had grown cold. He rubbed his hands together and breathed into them. But his breath misted before him and he soon couldn't feel his fingers. He had tried desperately to think of a way out of this, but had been able to think of nothing. He paced around the console, resigning himself to his fate. "Life support failing. I don't know if you'll ever hear this. I don't even know if you're both alive out there. But Clara, you were a mighty fine Doctor. Little Bird, I'm sorry. I should have done more." He said. He sat on the steps and turned his collar up to shield his ears against the cold.
Clara and Aderyn were in a brighter mood than he would have expected. They had found a glimmer of hope and were holding onto it. So far their plan was going well. Rigsy had proven himself to be a dab hand with a can of spray paint and his latest work of art had been stuck to the wall next to the track. The TARDIS was placed on a metal ledge on the other side of the wall and they waited.
"This is a ridiculous plan." Fenton grumbled under his breath.
"You can only say that if it fails." Aderyn said. They didn't have long to wait.
The creatures lurched and jerked their way down the tunnel until they came across a door. Whatever contraption their prey held had been set to work again. They put all of their power into turning this two dimensional door into a 3D one. But no matter how hard they tried, nothing happened. But they persevered. None of them realised it wasn't a real door. None of them saw the corners of the poster come away from the wall.
On the other side of the wall, the seige cube started to shake as it absorbed the power the creatures were throwing at the door Rigsy had painted on the back of the poster, the energy they were throwing through the wall.
"We need to move. Best not to be too close if this works." Aderyn said. She, Clara, Rigsy and Fenton stepped back. The cube flew off the ledge. It changed size and shape in mid air before landing amongst the creatures on the tracks.
They climbed quickly onto the track as a force field from the TARDIS sent the creatures flying in all directions and the Doctor's voice boomed out of the tannoy.
"I tried to talk. I want you to remember that. I tried to reach out, I tried to understand you, but I think that you understand us perfectly. And I think you just don't care. And I don't know whether you are here to invade, infiltrate or just replace us. I don't suppose it really matters now. You are monsters. That is the role you seem determined to play. So it seems I must play mine." The Doctor threw open the TARDIS doors, emerging looking no worse for wear "The man that stops the monsters. I'm sending you back to your own dimension. Who knows? Some of you may even survive the trip. And, if you do, remember this. You are not welcome here. This plane is protected. I am the Doctor." Clara threw him his sonic screwdriver and he caught it "And I name you The Boneless." He pointed his sonic at the force field and fizzes and zaps of energy hit the creatures, causing them to disintegrate with a horrid squeal. The Doctor smiled at Clara and Aderyn.