I corrected the drunken mistake.
I repaired the spot where the yarn snapped in the row two below the one I was working on. (FYI - I didn't tink back, with 600 stitch rows that just seemed too much work. Instead I dropped (carefully) about 10 stitches either side of the snap, back to the affected row. I joined a new length of yarn and reknit the stitches on the damaged row using that. I reknit the next row with the dropped stitches.)
Last night I bravely picked up the needles again. I knit along without calamity until I got an annoying work email. I put my knitting down to read the annoying email - and as I picked up the shawl again it snagged on something (I still don't know what) and the yarn snapped again!
More annoying -- this break was deep in the body of the shawl and I somehow lost it!! Because the shawl is now so large, I can't spread it out on the needles, and of course the knitting itself looks like wet noodles -- all of which makes searching for a snapped thread like looking for a needle in a haystack. I can't find the break - but I know it's in there. Waiting to cause havoc.
So, I carefully put the shawl down.
And I think I'll wait for a sign from the knitting gods before I pick it up again.