I force myself to stay calm and, patiently locating the handles by touch, I start to move, all the while thinking about how to eliminate the water if it were to reach my mouth. The only idea I can think of is to open the safety valve by my left ear: if I create controlled depressurisation, I should manage to let out some of the water, at least until it freezes through sublimation, which would stop the flow. But making a ‘hole’ in my spacesuit really would be a last resort.
As I read the phrase "eliminate the water", I wondered why he didn't consider the snorkel technique called "blast clearing":
The snorkeler expels water from the snorkel either with a sharp exhalation on return to the surface (blast clearing) or by tilting the head back shortly before reaching the surface and exhaling until reaching or breaking the surface (displacement method) and facing forward again before inhaling the next breath.
Obviously the displacement method won't work except in snorkeling, but blowing out a puff of air to push the water away seems like it would work. I mean, the water will go off to some other part of the spacesuit rather than blocking the trachea and drowning the occupant.
Bonus question: what are the odds that Luca's plan would have worked if he'd needed to exercise it?