Four soldiers jump into a motor boat and leave the dock. The next shot of them and every other shot shows that five men boarded the boat.
Cutting the airhose would not cause the diving bell to sink; only cutting the lifting-cable would release the unit and allow it to fall to the bottom.
After Steve rips the propellers off the patrol boat, the pirates try to race after the escapees, and the helmsman has trouble moving the throttle levers. Removing the propellers would not affect the movement of the throttle levers, it would just allow the engines to run at full speed with no resulting motion of the boat.
When Steve is seen swimming underwater to take the propeller off the boat, the swimmer appears to be wearing flippers. Steve was wearing just socks when he dove in.
Steve disguises himself as one of the soldiers and escorts Julio past another pair of soldiers to a jeep to escape. Santa Ventura is obviously a Latin country, so the soldiers would never have been fooled by a blonde haired, blue-eyed American looking soldier. It would be more believable if Julio were disguised as the soldier and Steve was the prisoner.
As the soldiers leave the dock in the small boat, the shadow of the camera is visible at the bottom of the screen.
When Steve drops off Julio a cruise ship is visible in the ocean background, it is extremely unlikely that the ship would be allowed in territorial waters if the country had severed ties as stated.