He and Kate , together escape through an opening at the top .
Lucas concludes that it is a massive piezoelectric crystal cluster which attains its resonant frequency due to seismic activities and creates the portal which can also help him to get back home .
Lucas and Kate , together escape through an opening at the top .
Lucas concludes that it is a massive piezoelectric crystal cluster which attains its resonant frequency due to seismic activities and creates the portal which can also help him to get back home .