She can cut the dome from the bed and push it over. (Or more likely float it off, since its partly metal.) When she first cuts into it, extremely cold gas spurts out from the gap, as if it was pressurized inside. It will disperse without causing harm, but its essentially like throwing the door open on a -40c windchill day. It turns slightly opaque as it wafts away, gravitating towards the floor, ostensibly heavy.

Up close, it looks like the power cell actually can be removed fairly trivially, like it's meant to be easily installed and removed when full. It's fairly warm, but not as hot as the other ones she collected, seemingly counteracted by all the cold gas and fluid occurring in here. The glowing blue tubes feel like they are filled with ice, and Ignatius's skin is... sort of cold? Which probably counts as terrifyingly low temperature for a fire elemental.

It seems a bit risky to try to reverse to polarity of the whole system, considering how volatile Ignatius's magic is. Disconnecting it, however, seems far more doable. It also seems possible to remove the plugs from the ends of Ignatius's arms and legs.

As for what is keeping him alive, nothing will strike Rita, Peridot, or Herbert as 'life support'. Generally speaking everything seems to be hurting rather than helping.

If Peridot does actually get in close enough to touch him, his muscles will flinch reflexively when she does.