No witnesses? Did this dude mean the MC should kill everyone in the crowded market? If not, I'm pretty sure there's gonna be witnesses. Considering the less than strictly legal nature of the businesses there, perhaps not any witnesses that will immediately report anything... but certainly witnesses that would sell information to a wealthy buyer. Or even just brownnose the nobles and their servants who come to investigate the missing noble for some other sort of potential gains.If the MC kill the whole group there will be no potential witness. Why would you leave someone with potential to harm you stay alive ?