Testing accomodations are generally done at a separate time. So students with an accomodation requiring a low distraction environment or extra test time would all take their test after the main test takers.
This came with the dual advantage of providing an alternate time for students who had excused absences to take the test as well.
TLDR: You don't normally see the students with accomodations during tests unless you also have an accomodation or you had a conflict with the test time/date.
And of course some professors do double time accommodations by having the students take the test with everyone else and then follow the teacher to their office to finish the exam afterwards but tbh I didn't see that very often.