Besides being the role of female actress Juliette Lewis in the Oliver Stone film "Natural Born Killers" there is more than one artist with this name (see links in the Wiki sources):
These are videos from concerts where Mallory Knox played, so they may be of other bands that played the concert as well.
Love in an Elevator
Firenze Rocks Festival 2017 Jun 23 - 25, 2017 Florence, Tuscany, Italy Added by Nurz
Mallory Knox / Lonely The Brave / Fatherson Mar 29, 2017 Edinburgh, Scotland, United Kingdom Added by Michael Quantrill
Butserfest Sep 10, 2016 Petersfield Added by Jwicks
Slam Dunk Festival 2016 (South) May 30, 2016 Hatfield, England, United Kingdom Added by Cpt Short