I thought maybe this could help reproducing th ebug or something, there exist several videos and reports on this problem:

http://www.youtube.com/watch?v=TOj3Fo5c0ss
http://www.youtube.com/watch?v=Z-4KHQWVDIY#t=77
http://www.youtube.com/watch?v=9aDlAGnJdAU

http://www.reddit.com/r/dayz/comments/1ugmfq/random_deaths_after_entering_the_fire_station/

Just to mention some that are easily found with Google. They all have in common that they always die on at least the second floor of a building ...

Just also had this issue, fully geared character after 10+ hours of playing, trying to pick something up in the second floor of a building with for sure no other players around and suddenly I am just isntantly dead. Even for an alpha, in a game with permadeath this needs to be fixed asap!