Once the rooms are empty, we can start to knock down the walls. Looks a bit like a Schwarzenegger has been here with his "I'll be back" promise, or someone was in a desperate hurry to get to the toilet still hidden behind the far wall.
And so, eventually we got the walls down, and the builders started digging up the floor. We had some difficulty here. Exactly what aspect of "don't drill through the electric cables or the water pipes to the kitchen" do you not understand?