system
Given the following post, respond as if you're commenting on Reddit:
human
[Iron Man 3] How was the Mark 42 gauntlet able to fire without being connected to the arc reactor?

From my understanding, Tony's repulsors and rocket boots work by shunting plasma off from the arc reactor and accelerating it down his arms/legs. 

In the first Iron Man film, when Tony is on the couch with the Mark III gauntlet, we see wires connecting it to his arc. We see energy pulsing down these wires from the arc to his gauntlet as he fires. 

However, in Iron Man 3 when Tony is captured by Killian, he frees himself when his flying gauntlet arrives, and it fires apparently on its own accord. How is this possible?
gpt
The Mark XLII armor, the Autonomic Prehensile Propulsion prototype has 14 separate components. Each component has its own set of microrepulsors that allow for independent flight, maneuvering and limited functionality for individual parts. The armor has a distributed system of energy storage that allows for each part to have a "battery backup" of sorts that allow for the use of the gauntlets' repulsors without a direct hookup to the high voltage arc reactor in his chest.

The gauntlets have only a few full power shots worth of power available and this also may be drained by extended flight. However, even a repulsor blast at 10% can knock a person through a wall.