Stormtroopers don't represent a threat anyway - they can't hit a thing
Maybe the cops were expecting:
https://www.google.com.au/imgres?imgurl=https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fthumb%2F0%2F07%2FFrance1918.jpg%2F300px-France1918.jpg&imgrefurl=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FStormtrooper&tbnid=Gc3QByp_LbLPBM&vet=12ahUKEwinjuGK9KLpAhV7DLcAHR1lB0IQMygAegUIARCDAg..i&docid=8crW_dRjFqzk-M&w=300&h=430&q=german%20stormtroopers&ved=2ahUKEwinjuGK9KLpAhV7DLcAHR1lB0IQMygAegUIARCDAg