What makes this custom magic item deal damage repeatedly?

Question

I have found this thing on Jormengand's first post

Using the custom magic item rules, we can get these brilliant items: The Staff of Instant Death This item, despite its name, is not a staff in the conventional sense, but a wondrous item bolted to the front of a quarterstaff. Each staff is keyed to a particular class or alignment, and a particular skill (such as truenamers and truespeak, or chaotic good and perform (kazoo)). When a creature that has trained in the relevant skill and is of the relevant class or alignment touches the staff, it activates, causing a whirling cone of energy in front of the wielder in a 15 foot cone. Any creature who touches the cone takes 1d4 points of damage. Half of this damage is fire damage, but the other half results directly from divine power and is not subject to fire resistance. This process is repeated until the character is dead, instantly killing any character who is not somehow immune to divine damage. Market Price: 600 gp. Prerequisites: burning hands; creator must have the Sanctum Spell feat, and either the consecrate spell or corrupt spell feat, and a feat such as arcane thesis (burning hands), easy metamagic (consecrate spell) or practical metamagic (corrupt spell). The item must be made outside the creator's sanctum. Some of the prerequisites can be ignored, but if either the sanctum prerequisite or the metamagic reducer prerequisite is ignored, the cost is 1200 GP. If both are ignored, the price is 7200 GP.

Emphasis mine. I get everything else, but what I don't understand is how the damage is repeating, so why does it repeatedly deal damage?

Answer 1

Nothing, because it doesn’t work.

This is a twisting of the custom magic item pricing guidelines, at best, though even that’s a stretch.

And those guidelines are found in the Dungeon Master’s Guide, and address the DM who wants to create a magic item and is seeking a decent, balanced price for them. More importantly, the guidelines start with

Many factors must be considered when determining the price of new magic items. The easiest way to come up with a price is to match the new item to an item that is already priced that price as a guide. Otherwise, […]

and end with

Not all items adhere to these formulas directly. The reasons for this are several. First and foremost, these few formulas aren’t enough to truly gauge the exact differences between items. The price of a magic item may be modified based on its actual worth. The formulas only provide a starting point. […]

An item annihilates everything in front of it? First step is to find other items that do that, and price accordingly. The last step is to “modif[y it] based on its actual worth.” No part of the rules ever suggests at any time that the guidelines give you “the” correct or official or valid price.

Furthermore, even by the guidelines, nothing on earth suggests that a “use-activated” item of burning hands (which is fundamentally what the “Staff of Instant Death” is) would be activated continuously just by holding it. The design is predicated on a “use” being defined as a non-action moment of contact, and that every such moment counts as another use and another application of burning hands. There is zero basis for any of that anywhere. “Use-activated” items always require actions to activate—actions that also do other things, such as make an attack, but actions none-the-less. A sword that shoots burning hands every time you swing it? Strong, “may [need to] be modified based on its actual worth,” but could legitimately be the sort of item that the guidelines are talking about. But this isn’t that. There’s no suggestion anywhere that this sort of thing could be legal.