Oh that's for the neck shaping. Just start using the yarn - leave a tail long enough to weave in later and knit the 2 sts to do the first BO. Binding off will keep the sts from being loose and it won't pull out. You would do the same thing if you have to 'join' 'rejoin' or 'attach' yarn to knit in another place too, the stitches won't unravel, and you can pull on the tail if the first few get a little loose.
sue- knitting heretic