There are some civilian deaths that are supposed to happen, like
Spoiler Severio Pelagia's demise during the Civil War questline,
but that beggar kicking the bucket seems pretty random to me. Maybe one of the guards was accidentally aggro'd by him and felled the poor fellow. Sad that you were his best friend, though, isn't it? I mean, Severio wrote me into his will because I sold some cabbages to him once. There sure are some lonely people in Skyrim.
