This series has been on a downhill slide (science wise) since season two,this episode looked like it was written by people from either Mad magazine or National Lampoon.
First lets look at the methane leak. Late in 2015 the Aliso Canyon gas leak started here in southern California and the nightly news was able to show infra red video of the gas leak- so how could a gas leak not be seen and detected by EVERY orbiting camera, NOAA and other agencies! Apparently the writers must have been living in a cave the last two years to not know this or they just think their viewers are stupid, either way I feel insulted.
As another has stated governments in the area of the leak would not take too kindly to having interlopers in their country without permission.
Now as to the singing it would have made more sense if it were all in the minds of the individuals and not actually sing out loud silliness.
In short the production staff has gone of the rails and are headed for cancellation if this nonsense keeps up!