well, I would say otherwise. Don't think of subspace as a tunnel, but rather as a wire, stretched between to platforms very high in the sky. If the wire is strong enough and you are smart enough, you can cross from one side to the other. But if lets say you blow something up while on the wire, lets say a Orion full with a s***load of Meson bombs, the wire will break.
Now physically thinking, when you vibrate in n dimensions (we know 11 thus far), and thus bend the time-space continuum, it takes a lot of energy. Nodes are like natural curves in time-space, sort of wormholes. But again, blowing the Orion mentioned above might and most probably will affect the node, altering its frequency or eliminating it.
At least that's what I could come up with in 10 minutes. I'll keep on thinking
LE: Fixed, sorry for that. A tad bit sleepy.