The internal valves inside the XRS helium insert use superconducting wiring, both in the valve motors themselves and in the leads that connect them to the outside. If the wires get hot when we're operating the valves, they will stop superconducting, leading to heating from the current flowing in them, which will increase the resistance further, causing more heating, et cetera, until they vaporize. That would be Very Bad™.
So we have a fancy system to detect this situation and immediately shut down the valve if it occurs. It also has a manual shutdown button, which was designed with an understanding of Fitts' Law.
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