Nope, the train doors will not suddenly open while the train is
moving.
This is because all of our MRT trains have a protection
system whereby when the train doors are open,the train will not
move even when the driver hits the accelerating button
accidently.(Including driverless trains)
Like wised when the train is moving and the driver hits the door
opening button accidently ,the doors will not open until the train
stops.
Had a friend who leaned against a NEL train door once while the
train was moving. The door opened slightly and the train jerked a
little as if it detected the problem but it did not ebrake to a
halt. My friend had a little shock and naturally stopped leaning
against it. The door closed back by itself and everything resumed
to normal as if nothing happened.
I personally saw this happen on BPLRT too on 2 Nov 1999 - The
first day of opening (1 day before official opening) a woman leaned
against the door and it opened slightly and the train jerked
too.
I know it seems to sway from what linwei is asking but just
sharing some experiences. I agree with you that doors cannot be
opened via controls when in motion.