I feel like some of Laurentius' characterization was lost when they condensed the related quests in the ARR revamp. The old way of having to chase him around, watch what he was doing and listening to him talk to himself spoke volumes compared to the abbreviated version we now get.

He was both opportunist and coward. That led to him being easily manipulated because he wanted to get rich with little to no effort and risk.

I do believe that murder wasn't his style but he was already in too deep by Baelsar's Wall and not doing it would have meant his own death, probably at Yuyuhase's hands.