I didn't even make it to 20% of The Fifth Vial before I decided to throw in the towel. For a thriller it starts out incredibly slow. Maybe, I have been spoiled by the few thrillers that I have read because they all just jumped right into the action.
Palmer spends the first 50 pages (probably more but I didn't wait to find out) developing the characters and I did not care for the ones that I had met. They had interesting backstories and I thought that he did a nice job of create a history for them.
Overall, the writing was just not engaging enough of me to continue. It was too easy for me to put this one down and forget about it.