He's rigid because he's autistic- What's your excuse?

Abe had a problem in resource room because the teacher had promised him that he could play on the computer for five minutes at the end of the period if he did all his work nicely.  Everything went well until Abe's watch said it was five minutes until the end of the period.  The classroom clock was slow so the teacher wouldn't let him use the computer until the room clock showed the time they had agreed on.  Abe has a thing about time accuracy and his watch is synced to some satellite somewhere so he knew his time was correct.  He had a meltdown because he didn't think it was fair and ended up missing all of Social Studies because he was calming down in the psychologist's office. 
      O.K.  It would be great if Abe could cope with the fact that sometimes the person in authority is wrong but you just have to accept it and make the best of it.  However, he is not there at this point of time.  The real question is why the teacher made such a big deal out of it?  After all, he had done his work nicely the entire period.  Did a couple of minutes make a difference to her?  The point of the reinforcer is to be able to give them the reinforcer instead of getting involved in a power struggle over the time.  If she had been flexible, instead of freaking out he could have been reinforced for working well and would have happily gone off to class. Was it worth trying to control him?
     I ended up speaking to the teacher about it and she isn't a bad person.  I just think that she had no idea what she was getting into.  That's pretty scary considering that she is a special education teacher.  I did get the sense that she was willing to listen and learn, which is a good thing.  I think she felt that she needed to be the one in control but by trying to get Abe to back down she learned that Abe isn't going to back down.  Once he is in a rage state I think he is incapable of thinking clearly or backing down.  He's a different person than the sweet agreeable young man he usually is.  Let's hope that the teacher is a one trial learner.