Here's my take on Lane's basic point, which seems unarguable to me.
Assume that science can explain what currently is unexplainable. If significant mysteries eventually remain that science can't explain, this is where supernaturalism, or at least a radical restructuring of how we look upon reality, can be seriously explored.
This is much different from the "god of the gaps" approach where whatever science can't currently explain is taken as proof of God's existence.
Meaning, a scientific gap is simply a present-moment deficiency in understanding. A scientific remainder is what is left after a lengthy process of research, study, theorizing, testing, debating, hypothesizing.
For example, the ultimate nature of consciousness is still largely unexplained by modern science.
It's unclear whether this is a philosophical/conceptual problem -- maybe there is nothing to explain since consciousness is just what a highly evolved physical brain produces -- or whether consciousness stands apart from neurons, brain chemicals, and such.
Either way, it would be a mistake to embrace mystical notions of soul or whatever just because science is still working on understanding how it is we are able to consciously understand reality.
History is filled with examples of how people believed in supernatural causes of worldly phenomena which later could be persuasively explained via material laws of nature. There may indeed be explanatory "remainders" after modern science has done its thing in an exhaustive manner.
But we're nowhere near the end of scientific progress. The best bet is on science, not religion, as humanity's best guide to knowing reality.