You're forgetting that Dylan don't know what you, as the player, know for a long time. You know the police can't deal with Ayden, but Dylan didn't know that. O.K, he knew about Aiden's uncle, but as L&P already mentioned (and as natural as it is), Dylan didn't knew exactly what Ayden was capable of, nor he knew where he will take it.
H.B compared it with someone contracting a hitman to commit a murder, but this comparison is B.S! Better compare it with someone contracting a thug to punch someone, but instead the thug pulls out a shotgun and shoot that someone 12 times... Dylan couldn't know where Ayden will take his simple task. We know where he took it, because we have a different pov, but Dylan didn't have this perspective. For sure he's dumb, very dumb. But Some here take this way to personally... (imo)