Basic blender went bad (motor ran but spindle wasn’t rotating). I wanted to disassemble to see if it could be repaired. Three of the four screws were Phillips head. I had to cut the casing open in order to discover why I couldn’t unscrew the fourth. It was a slotted spanner.
Do some comprehending. Yes he had to do that. But it was because he was using the wrong bit.
He had to see which bit to use
That can be accomplished non-destructively.