I just started playing tonight and decided I wanted to mark Campbell with the Heretic's Brand and keep Curnow alive. So I smashed both glasses and hid in the corner behind the changing thing. I shot Campbell with the sleeper dart which caused Curnow to run to the alarm. I couldn't get him with a sleeper dart before he hit the alarm, which I immediately turned off and knocked out the one guard who came running (I had killed the rest on that floor). I proceeded to mark Campbell and I got check marks for the non-lethal method and for keeping Curnow alive.
...then I get back to base and I talked to Callista Curnow, who says something along the lines of, "My uncle is dead, isn't he? He never came back. I shouldn't have expected anything else." Wait, what? Did Campbell tell the guards to kill him? Maybe they thought Curnow marked Campbell. I dunno. I'm just confused. Anyone else have this happen?