This seems minor and probably is, but try dodging gunfire from the docks when your character refuses to submerge out in deep water. Makes it rather frustrating. Or try sneaking up to the docks to exit the water only to be caught with your arm out and trying to submerge. You, as a SEAL type of soldier, should be able to slowly exit the water with no sound, and dissappear into it fast, without much of a trace at all.