Sean mostly covers the boat and the bomb, making sure that nobody does anything fancy, like stealthily disembarking, including under the water, disabling the bomb, aiming at Tariq and Richard, etc. The net has been already set up, covering Bart, Sean and dogs, but Tariq took his time almost to the limit, so Sean does not expect the man here in the hiding. Maybe he will side with Richard or take some other spot.