I hadn't thought about that before, but you're right, he was exceptionally unlucky/clumsy so it's entirely possible that he was doing it all on purpose. He 'accidentally' pushed Toby into the water and then somehow managed to save him - it could all have been a calculated set-up on Collins' part, he knew there was a very high probability of being able to rescue Toby which would make him the hero (and make even Toby start to believe he genuinely had changed) that he took the chance. And he knew there was a very high probability that Cabe would not just let him die (and he already had Toby on side at that stage) so, again, he took a calculated risk that the team would save him if he was 'accidentally' unable to escape from the vehicle.
Sneaky.
