Good post, Fieldsroyal. I think your comment about the level of comfort with death and violence reflects what many of us have been trying to say. It is a bit mercenary, in nature.
I wonder to who Sam owed the apparent massive debt (the possible motive - and the possible reason for the prior confrontational home, not so unusual in the drug world). Was it Boscaino? Was it Dyball? Was it both of them jointly?
Because if it was Boscaino, as others here have mentioned his activities with drugs were quite well known about town, and Sam was apparently seen visiting his house quite regularly, then why did Dyball get himself involved?