How does Joe think he can get away with this murder and keep on living and marrying his fiance? Chad's relationship with Joe was official to him so it's likely he told his friends about his weekend trip. Someone will eventually report Chad missing and the police will start looking for Joe. And potentially find Molly as a witness. Joe's plan is built on thin ice.
- It's fair to say that Joe's marbles might not all be in the same bag at this point, so to speak, so he might be overestimating his chances of getting away with it. But it's not wholly unbelievable. Joe is clearly living a double life, meaning he's got another identity to escape into; the cabin is very remote, meaning no one is going to be checking up on Chas any time soon; Molly has been fired, so also won't be checking up on Chas any time soon (and also, how many people will know the name of the cleaner of their remote cabin?); and it's going to take a bit of time for people to realise that Chas is missing and report his disappearance to the police, who will then take a bit of time to find him and investigate the scene. That all gives Joe some time to essentially disappear with his new fiance.
- The police are also only going to look for Chas if they have a reason to - Joe's not going to report him missing, Mollie's been sacked and has no reason to think twice and eventually Chas' body will decompose or be eaten, so Joe could conceivably dispose of it.
- If Joe was questioned, he'd give some plausible location he last saw him, possibly even accurate enough to give the police a group of red herring leads. He's not suspected of anything, and if him and Mick get a truck and collect the bath before dumping it in the ocean or off a cliff, well, by the time the police might figure out he's involved, the evidence is already destroyed.
