Hall with locked doors

[Fleemo17]

[quote=Thaliur]

Spoiler below!

You can simply bash the fuse box with a small rock you can find near the place where a part of the wall fell down. Then you can get to the cables inside.

I tried using this early on but somehow didn't get the desired result. Now that I've read this and have gone back to the fusebox to try again, there's no rock to be found. None of the remaining shards next to the crumbling wall can be picked up. Are there any other workable rocks to be found or must I start from scratch???