From Clip Studio Paint's "record" feature. Which I remembered to start after I'd half-inked the first panel.
This page might be of interest because it uses a lot of layers. The background of Panel 1 was drawn in-full, without any of the characters or debris, then copied to panels 2 and 3. Saved me a butt-load of time.
Normally I'll color a whole page by stages (flats, tones, etc.) but this time I worked on panels 1-3 separately from panels 4-6.