maybe the line 'mutated' came from this article..

[link to www.unisci.com]

'When Neutrinos Change Type, Some Must Have Mass'

'Since the early 1970s, several experiments have detected neutrinos arriving on Earth, but they have found only a fraction of the number expected from detailed theories of energy production in the Sun.

This meant there was either something wrong with our theories of the Sun, or our understanding of neutrinos.

It turns out that our theories of how the Sun is powered seem to be correct, according to a team of scientists from the UK, the US and Canada whose latest results from research into solar neutrinos were announced on Saturday (20 April).

What's more, these ghostly particles have "chameleon" capabilities, changing from one type of neutrino into another on their journey from the Sun to Earth.'

perhaps the whole film is based on this finding?

do they interact with that huge sheet of plasma above the earth and from being virtually massless when they leave the sun, they suddenly become objects with far more mass?

found another 'mutate' reference to neutrinos too, in a scientific article, dated from 1995..

[link to www.emsb.qc.ca]

'Detecting neutrinos has been an important way of providing evidence for theoretical models of how the sun shines. For about 30 years those theories were in doubt because they predicted a far greater number of neutrinos than were actually detected. Then an experiment in Sudbury Ontario proved that if all three types neutrinos were measured, then the theoretical prediction was essentially correct. Electron neutrinos "mutated" into muon and tau neutrinos on their way to earth. Originally only electron neutrinos had been picked up by early experiments, leading to the erroneous conclusion that the sun was actually producing few electron neutrinos. '

perhaps that vast tank of water, deep underground in the movie was analogous to the liquid molten core of the planet?