1: if you go to the hardmode jungle as soon as hardmode is initiated, you will get squashed because you only have molten armor. dude, it's hard to survive there even with turtle armor sometimes.
2: the droprate of the uzi is pretty low, and it requires you to kill a bunch of enemies several tiers above you with prehardmode stuff, it's like trying to get key molds except you have worse armor. if the player in question is a ranger player, they will likely have only necro armor, which is even worse defense-wise than molten, and so they will get squashed like a grape under a semi truck.