I believe that a large portion of the movie was him experiencing implanted dreams, and a lot suggests this is the case. My thoughts (having forgotten a lot of the character names):
- the news feed at the start of the movie talks about some kind of war going on at mars but, unless I don't remember correctly, doesn't go into details about mutants
- they explicitly describe how the movie will play out on multiple occasions, and when he goes into the recall machine you can see a brunette woman on the monitor that would inspire his love interest which is intended to be a big hint
- there are very abrupt changes that happen in the movie with no build up. Once he wakes up in the recall machine, it's an action movie full of bad guys after him and people in his life he thought were normal are out to kill him too
- and on the note of people in his life becoming henchmen trying to stop him, I interpret Quaid as taking characters or objects that are against his dreams of going to Mars or going into the recall machine and turning them into villains he has to stop: his wife, the construction worker, and even the recall machine itself which is for some reason in the villain's lair and could be used to effectively end the dream he's having
- the man sweating is ambiguous, but upon a rewatch with the assumption that he actually is a fail safe that Quaid rejects, you can notice how the movie presents the dream's action and story as having been completely interrupted by him. The moment the man is shot dead, he's completely forgotten, never acknowledged by the villains or any other character, and immediately some guys crash through the wall to start a new action sequence