Path Tool - Joining

I do quite a bit of photo editing and im stumped as to how i solve this problem.

The majority of my editing is of people and removing the background so i just have their face. Im using the path tool to create a path around that person and then creating a mask from that path, i find this works the best for me.

However the problem is when i accidentally miss out a node when i zoom or something which results in a "break" in the path, i usually don't notice this and when i get to the end of the path i cant close it. To demonstrate this ive mocked up a small scale:



What i want to do is continue the path from node 2 to node 3 however i can only connect node 2 to node 1 any ideas?

Thanks

Nino