There is a stage past [flagged] where a post can also be [dead]. You only see dead posts if you have showdead=yes in your settings. So you may have seen their

There is a stage past [flagged] where a post can also be [dead]. You only see dead posts if you have showdead=yes in your settings. So you may have seen their comment before it was killed, or you may have showdead=yes in your settings.