You are relating many different things which do not correlate.
Instant boiling of heated water in a microwave that was not previously boiling beforehand is called superheated liquid. Clean pure water in a very clean container slowly heated in a microwave does not have many nucleation possibilities. The water actually becomes hotter then 212F (100C) without boiling. The moment the water is disturbed by nudging the cup it instantly burst in a boil. Very violent and a well documented household hazard.
see:Superheating - Wikipedia, the free encyclopedia
The pressure cooker works by increase the air pressure above the water hence preventing the water from boiling at 100C but at a higher temp. The food cooks faster. The weight on top is precisely calibrated to increase the boiling temp to 125C or so. If you open the cooker when under pressure all the water inside will be at 125C but the air pressure suddenly comes back to normal (boil at 100C). Again the superheated water will burst like a bomb.
see:Pressure cooking - Wikipedia, the free encyclopedia
When you vacuum out the air from a flask of water it will appear to boil but actually what is happening is dissolved air escapes in small bubbles at first them larger (boiling like). This is called degassing. The water will become still afterwards and remain as such. To boil water at a lower temp (around 60C), you must actively maintain a vacuum and heat the water to 60C and it will boil.
see:Degasification - Wikipedia, the free encyclopedia
I grant you that adding oil to pasta water will reduce the foaming but again this effect is minimal. The starch will still gel the water and the effect of the oil is minimal because oil does not dissolve in water and floats so cannot prevent the gelling to take place.
Experiment this: fill a pot halfway with water, bring to a boil, add pasta wait till it boils again. Let the pasta overcook then when foam appears add some oil, the foam will be knocked down (true) but wait... it will come back. Momentarily, the oil will take some heat away from the water and prevent it from boiling for a little while. Oil can take a lot of heat but the water will recover again.
If oil prevented the starch from reacting, the pasta would not soak up water, swell or gelatinize. The pasta would be adversely affected which is not the case.
Even better: use 2 identical pots, same amount of water and same pasta and make a parallel experiment, one with and one without oil. You will notice how feeble the effect really is.
I hope others can corroborate, at least partly, with what I am saying here?