Change would to could for this to be more appropriate or accurate.

Chain breakage isn't that rare (even when closed correctly), and chains almost always break at the worst of times (when tension is fairly high), yet there are not that many injuries arising from chain breakage. There are even fewer serious injuries, though they do happen occasionally.

Breaking a chain isn't fun, and it could cause an injury, but isn't likely to. The typical chain breakage injury is cuts to the calf from the chairing or the chain whipping forward. Actually the most common chain breakage injury is to the front derailleur, as the chain whips forward snagging the cage and tearing it off the bike.