Corrected entry: It is mentioned in the extra commentary that a production error caused the Endoskeleton to be made of STEEL - extremely heavy - causing Special effects shots to require multiple puppeteers. This is partly the reason why the Endoskeleton moves so slowly while the T800+organic skin moves so quickly.
Tailkinker
16th Jun 2007
Correction: Movie mistakes are about on-screen errors, not foul-ups in prop fabrication. While this did happen, hence the citation in the commentary, it cannot be said to count as a movie mistake. Even the disparity in movement speed between the flesh-covered cyborg and the exposed endoskeleton is adequately explained within the film as being due to damage sustained, so that cannot really be considered error-worthy either. I suggest that you resubmit as trivia.
Tailkinker ★