If one pilot tries to ram it into the ground, or just throttles back, the other pilot can fight them for the controls and possibly prevent a crash. When those switches are flipped the engines almost immediately flame out. Even if the other pilot quickly flips them back and prevents the first pilot from doing anything else, it takes time for the engines to automatically relight and spool back up. Done right around liftoff, which seems to be the case from the RAT deployment, there might not be anything the other pilot can do no matter how fast they act.
Edit: According to the flight data recorder, the cutoff switches were flipped 3 seconds after takeoff, one was flipped back on 10 seconds later, the other flipped back 4 seconds after that, and the recording ended 15 seconds later.
If one pilot tries to ram it into the ground, or just throttles back, the other pilot can fight them for the controls and possibly prevent a crash. When those switches are flipped the engines almost immediately flame out. Even if the other pilot quickly flips them back and prevents the first pilot from doing anything else, it takes time for the engines to automatically relight and spool back up. Done right around liftoff, which seems to be the case from the RAT deployment, there might not be anything the other pilot can do no matter how fast they act.
Edit: According to the flight data recorder, the cutoff switches were flipped 3 seconds after takeoff, one was flipped back on 10 seconds later, the other flipped back 4 seconds after that, and the recording ended 15 seconds later.