How does the bloodstone work?
Assuming bloodstone is an item or omen, the traitor used this incorrectly. Items are explicitly listed as being usable “once during your turn”. Some confusion may arise from the fact that later in that same section (Rulebook, page 11), it lists the five potential things that you can do with an item (use, trade, drop, steal, pick up), only one of which you can do a turn. While this does not explicitly state your turn, it can be inferred from the section.  Also, on page 6, “Use item and omen cards” is listed under a heading of “ON YOUR TURN...”. 

I could not find the rules for the Widow's Walk expansion online, but I don't recall them changing this aspect of item use.