4:30 You're not supposed to cut a carpet tile over other tiles such as the guy did here. He unnecessarily cuts numerous times when the tile was already all the way cut on the first pass. He ended up cutting the other tile beneath, leaving damage. When he removes the cut carpet tile look to the right side of where the tile was laying and you'll see the damage. This is something this instructional video should've pointed out, but failed to. Most installers I've seen use either a box flap or a spare carpet tile as their cutting board to place beneath each tile being cut to avoid damaging the ones beneath.
