Plot Holes to Drive a Truck Through

OK, I know I'm not supposed to take these Lifetime TV movies seriously, or pretend that they hold together in any logical way. And many of the plot holes in this particularly bad movie were already discussed here in other comments (not the least being that identical twins are never truly identical, and the daughter would be able to tell the two of them apart instantly). But one in particular had me literally screaming at the screen.

Early in the movie we have the mother and daughter singing "their song" together. Later, in the hospital, when the mother was in the coma, the daughter sang the same song to her mother, and she responded.

Then again later, when the mother wakes up but can't remember anything, the daughter mentions that smells and sounds will often trigger memories. So, let's think - could there be a sound, maybe a song, they could use to help the mother recover her memories? Ya think? But no; that would have been too easy. Instead, we had to be subjected to a (literal) cliffhanger of an ending that also made no sense (they were running toward a cliff they had to know was there, since they had spent many times at the cabin?).

I seriously wonder how these movies are written. Are the writers under a timeline that forces them to finish the scripts before any of these glaring errors can be corrected? The writers can't be so bad as to just let these things go, can they? Maybe they can...