The title, "Get Out and Get Under," comes from a popular 1913 song, "He'd Have To Get Under - Get Out And Get Under (To Fix Up His Automobile)" (Music by Maurice Abrahams; Lyrics by Grant Clarke and Edgar Leslie). Robert Israel's score in the 2004 alternate version frequently uses melodies from this song.
Rare and early depiction of a junkie and drug use - in this case cocaine.
In an early close-up in the photography studio, you can really see the damage Lloyd suffered to his face in the prop bomb explosion that occurred at the Witzel Studio on 14 August 1919. His face would eventually heal, but he lost the thumb and forefinger of right hand and he adopted the use of a prosthetic rubber glove (which looked unnaturally stiff) for the remainder of his film career.
Harold's car is a 1920 Ford Model T "Runabout". Over 1,400,000 were made that model year, priced at $395 ($5,150 in 2018).
The first police officer to chase after Harold is riding a 1920 Harley-Davidson model 20J (aka "J-Twin"). The second officer that pulls up behind is on a 1920 Henderson Model K.