If the thermal runaway condition creates an error message, then you can detect it and make a web call with my NodeDSF solution.
You can configure NodeDSF to watch for status changes or error/warning messages containing specific text, and then trigger a http post/get, or fire mqtt, or send an email, etc etc.
I know that heater faults create error messages, but I am not sure specifically what happens on a thermal runaway - I have found that normally any issue will create an error or warning message.
(Link in my sig)