In most engines the temp sender is nothing but a high temp senistivity resistor, as the temp increases, as I recall the resistance increases (positive Temp coefficient)
If the wire comes loose, you are now at "infinite" resistance.. or FULL SCALE on the temp meter.. it is called "Fail Safe" that is it fails in the position you find most alarming.
Fuel tanks.. If the wire comes loose.. read EMPTY,, for the same reason.
Of course your question is: Were we REALLY overheated or not?
Check the coolant recovery bottle.. (engine cold) if the level of liquid is normal.. You were not,, Overheat will usually boil off some of the liquid... So if it's still at the "Cold" level. you are good.
Home is where I park it!