How “immortal” are the sinners?

I’m a relatively new Hazbin Hotel fan, and there’s something I haven’t completely understood yet.

I know that sinners can be killed by angelic steel and by that angelic beam Adam used, but other than that how can sinners be killed? Can sinners kill each other? And how?

I’ve also noticed that Vox pulverized a random npc with his teleport, did he die?