anxiety, perfectionism, crash, fake apathy... just all a bunch of emotional parachutes so that failure is under complete personal emotional control... need a new parachute other than a sloppy apathetic defeatist approach.

brainstorm... other controls...
1) mine was speed with lots of rules like never double-checking work, can't write down my math, some were actually helpful like a five or ten second rule on language questions, then move onto the next one.
I never did practice tests, but maybe focusing on speed and losing big time for dumb mistakes to self-challenge is an approach?

2) I think OCD type thoughts can be ways of asserting controls and externalizing ownership. She could ritualize her work area to have everything just so; then if something goes wrong it isn't a capability issue it is the fault of a ritual failure.

3) Along those lines, having lucky things

4) Alter test pattern... do even numbers first... etc.

5) since ymmv, some other emotional parachute that makes sense for her

Only advice I've ever given to anyone taking a standardized test was to have a half cup of coffee before the test.