What does Misha find that brings him hope?

Misha finds a hole in the wall.... a way to get to the other side.

All that day I walked and looked, walked and looked. At last I saw something. It was not far from the uniform factory. There was a break in the bricks. It was low enough for me to reach. It was two bricks wide. I didn’t know it then, but it was a drain hole of some sort. It
would never occur to them that anyone could squeeze through a space two bricks wide