I love words and phrases like this that can serve so many different grammatical functions without a change in spelling.

pell-mell (pell-mell): / pel-mel /
adverb

(1) in confused or disorderly, headlong haste; in a frantic, recklessly hurried manner
(2) in a messy or jumbled manner; in mingled confusion or disorder

adjective

(1) disorderly, confused, or indiscriminate
(2) rash; precipitate; overhasty

noun

(1) confusion or disorder; a jumbled or helter-skelter condition, mass, crowd, situation, etc.
(2) headlong, disorderly haste

[Via French pêle-mêle from Middle French pelemele from Old French pesle mesle, a playful, rhyming compound based on mesler meaning “to mix.”]

Usage: The crowd ran pell-mell into the store as soon as the doors opened.