I don't know what kind of bow the Thunderhorn Coupe is (recurve, longbow, self, laminate, etc.), but here's what I think:
Check that bow extremely carefully for cracks/splintering/etc -- the WHOLE bow, not just the riser/grip area! Flex the bow -- carefully! -- while looking for damage, sometimes it can be harder to find than the Invisible Man... I've never had a string break the way you describe, but I have had a Flemish come apart while stringing the bow (I was given - and took - some really bad advice); I was using a bow-stringer, and it's the only thing that kept the bow from **snapping** back (things could've been nasty, otherwise).
I have seen a couple of bows after they suffered string breakage, and they were not pretty. Don't take any unnecessary chances.