Entertainment....all the movies were pretty unbelieveable. I mean, he should've died many, many times. Blown up, shot up, beat up. The scenario would seem to me to be one of intervene or escape and evade. For the sake of the movie it was intervene for the chance to rescue his ex-wife...I mean...come on! I wouldn't walk across the street to spit on my ex-wife if she was on fire! The bad guy's were extemely compliant in not killing hostages, going after him one at a time, and dying relatively easily except for the two or three big bad guys...kinda like video games.
What would I have done? Heck...don't know. If I had training and abilities maybe intervene. But I'd have to be one major bad ass myself. It my current state...escape and evade....get out and get help.
Now...Siegals movies...He doesn't get all beat up and shot up and blown up like Bruce does in his flicks. And he's supposedly this real hard case, highly trained, extremely dangerous man who retired from the teams to follow his captain around and be his cook. Could happen that way. But they still track him down one or two at at time and don't kill the hostages. I don't think that would happen in real life. I think they'd start killing hostages and send a team of guys to track you down and kill you.
As for the SEAL teams taking ships...oh yeah...it is done. I have a friend in the CG. Their ship was tied up at Alameda. They were told they were going to be the subject of a SEAL exercise and told to prepare themselves, as this would happen during the night watches on this night. So they doubled the watch and patroled the rails. Next thing they know the captain gets a phone call, is told the SEALS have came and gone, and for proof to go look in the engine room. They found a "bomb" there with a note.