[PLP]

sounds like head gasket to me...
it should not eject coolant at all. There might be some burp or level rise, but not spitting.
Spitting would suggest air coming through.

Not sure if that could work here, but on other cars the best test was to rev the engine (coolant would rise and spit) and let off the gas (level would drop and some coolant would be gone).
The former says gases get through the gasket, the latter suggests liquid got sucked into the engine.

If it was overheated - it is hard to judge what exactly it means.
Was it 120 C for a couple of minutes or was it 150 C and coolant was gone? Engine will work OK with coolant is even at 150 C, but the coolant must be present in liquid form.
Once it starts evaporating - well, no more cooling there.