Simple achievement to get but hard to perform. Pan is a one of the melee weapons and the only bulletproof shield in the game.
Early game (can be done in solo/duo/squad)
Simply (and bit of luck) just land in a spot that is preferably in large house settlement, military base etc. Then pray RNG gods for these reasons; firstly if there is a another player(s) be quick enough to find a pan and whackka that enemy player till he/she dies BEFORE he/she will get any of weapons or just fist fights you to death. Secondly pray that you will have a pan in that location where you land because these things spawn in random.
Late game (can be done in duo or squad)
When you down an enemy, just simply go near him and kill him with you're pan if you have any of those with you.
EDIT NOTES:
1. If you’re teammate downs an enemy but you will deal the finishing blow, you will NOT get the achievement because the game registers kills for the player who has firstly downed that particular enemy.
2. The pan kill will register and the achievement will unlock if you will down an enemy first with an different gun than using pan. For example: if you down and enemy first using M16A4 and then deal the finishing blow using pan, you will then get the achievement. This is how I got it.