Other mistake: In the scene after Arnold kills the construction hoods he goes home to Sharon Stone and tries to convince her that it was real by showing her his bloody hands with which he was grabbing her shoulders, yet there is no blood on her or the appliances he turned off upon entering the apartment.
Other mistake: The title 'Publicity' is misspelled as 'Publicty' in the end credits. (01:46:30)
Other mistake: When Quaid goes through the x-ray machine the first time, the person behind the man with the dog isn't shown to be carrying anything (there's no purple object shown). But then later the purple object is seen.
Suggested correction: Could simply be someone else with an item passing the person without any. He was walking very slow and certainly 1 person passed him, could be another one did as well.
Two people would have had to pass him and there's nothing to indicate 2 additional people were walking that much faster than him, or close to him.
They were off camera before. 1 person definitely did pass him so a second person doing the same is not unlikely.
They weren't off screen long enough.
I've seen this part multiple times. Who you see behind Quaid before entering the machine is first a woman with a handbag, then a man with mustache and case, then a blind man with a dog, after him a woman with a handbag again and more people. Now, the man with the mustache and case and the second woman with the handbag probably paused before entering the machine because we don't see them when Quaid passes, only the first woman with a bag, then a blind man with a dog and then a man with nothing. So both must have then sped up and then passed the man holding nothing. You see them walking faster than the others too. Not illogical when people are rushing to work or home either.
Other mistake: After Arnold kills Harry and his gang at the beginning, how did that blood splatter get on the wall behind him to his right? He shot the henchman standing in that position from the back and the other who was shot was shot standing to the left side of the wall. So there is no explanation why the splatter is there.