I'm amazed that people get boil-over in 30 seconds. I would've expected at least 5 minutes from a cold start (unless cold start means sitting in the sun in 110F weather or something like that, but still wouldn't expect 30s).
Engine Ice may well prevent boil-over, but as straight water has a higher heat capacity than anything else it'll run cooler on straight water (unless you're boiling over). The water moves the heat from the engine to the radiators more efficiently, it just boils at a lower temp too.
Running straight water is a bad idea IMO. No corrosion protection. I've run straight coolant in many of my bikes without fans, due to extreme hill climbing. Does it run hotter. Yes. Hasn't hurt anything since 1989 on the cr500's.