My naive assumption is that there’s a combination of two factors going on: 1) the blast force will be proportional to the area through which it’s transmitted, a

My naive assumption is that there’s a combination of two factors going on: 1) the blast force will be proportional to the area through which it’s transmitted, and a narrow hose will have a lot less area than the lid of a can, and 2) if the hose is fairly flexible rubber, there will be significant reduction of the force over the length of the tube.