Dog on the frame?

I got a bit carried away warping up some fine wool so it's turning out rather on the wide side. It was intended to be a hood, hairnet or snood, depending on how big it turned out, but after about 8 rows, it's clearly going to be too wide for anything like that. It's too fine to waste on a bag, but not long enough for clothing either. (It started about 2 foot long.) I'd either have to make a matching (or at least the same size) piece for the other side, or find some way of putting a slit in where I've already worked interlinking sprang. The more I think about it the more I think this may be possible.

If I draw a thread (or perhaps a pair to keep things even) from where I want the neck slit or armholes to be, the rest won't actually be able to unravel will it?

 

*and refasten the ends (sewing them in when it's finished).