When RO goes looking for the lavatory and enters the service area, he passes by a door without an outside latch. Moments later, he is locked inside the same door with a latch that appeared out of nowhere.
When the boat exploded in the first scene, the Hammersley crew were at least 500 meters from it. Several crew members were thrown off the Zodiac. At that distance, the shock wave would not be significant enough to knock anyone overboard.
After the Hammersley shot the boat speeding toward them and it exploded, it would have continued moving forward. Yet, in the next shot, the boat was sitting still.