Thomas is pretty pissed at Minho for leaving a newbie like him all alone, but the noises are getting louder so he doesn't have time to waste.
He realizes that he just can't leave a friend to die. Even a grumpy one like Alby. Thomas tries to carry Alby, but he's so heavy that they both fall to the ground. He tries to drag him, and admits that they won't get very far that way either.
Analyzing the situation, Thomas sees that running is not his best bet because he can't take Alby with him, and he has no idea what the Maze is like. So, even though Minho told him the ivy was a lost cause, he decides that's his plan.
After several attempts at different methods, Thomas devises a way to tie himself and Alby into the vines, and then hoist them up foot by foot.
When they are about thirty feet off the ground, he is so exhausted that he decides this is where they will take their stand. He still has no idea what to expect, but he doesn't have a ton of options either.
As the Grievers close in on him, he sees a beetle blade within inches from his face hanging on the wall beside him. It looks like a silver metallic lizard with twelve jointed legs and a red beam of light shining from its head. More importantly, though, Thomas is able to confirm that written on its back is the word "WICKED."
The beetle blade scurries into the ivy as the first Griever approaches the wall.