Fridge Logic: As with "The Dalek Invasion of Earth," Dr. Who and his friends escape an intelligence test. Viewers may wonder why an intelligence test is a necessary step to becoming a Roboman. The authors of the nonfiction volume The Discontinuity Guide speculate that the test is a way of eliminating the more intelligent candidates!
The less intelligent (for lack of a better word) are clearly less of a threat to the Daleks than anyone with a high level of scientific or engineering knowledge as the main thing that the Daleks have over us is their huge technological advantage. If the humans were to start reverse-engineering that technology or turn it against them somehow then they would be in serious trouble - which is exactly what the Doctor does in the film's conclusion. Why Don't You Just Shoot Him? is in full effect here of course, but the TV series is just as guilty of that.