If the windscreen wipers begin to move while you are changing the wiper blades, you can be trapped by the wiper arm.
When the engine bonnet is open, and the windscreen wipers are set in motion, you can be trapped by the wiper linkage.
If the wiper blades are worn out, they will not wipe the windscreen properly. Replace the wiper blades twice a year, preferably in spring and autumn.
Driver's side: long wiper blade
Front passenger side: short wiper blade