Flaps in turns. Hmmmm, maybe we should also stop anyone fiddling with the engine(s) in a turn in case something spooky goes on?
That said, I think it is really good teaching/learning practice to set flaps in isolation when Bloggs is struggling with Ex12/13. The student needs to become familiar with the effects of changing configuration - there needs to be a natural elevator input to counter any shenanigans caused by the flaps travelling or reaching their desired state.
They also need to get a routine going and we all know (don't we?) that in a C152, 1600-1700 rpm, level attitude, white arc, two stages of flap maintaining the level attitude until reducing below 70kts, lower the nose to three fingers and Bob is your uncle.
Whopity, I disagree. That looks like a classic critical engine-Vmca faff to me. Sure, there was probably a resultant stall/spin.