What's worse - colleges seeing your bad subject tests scores or no subject tests at all?

Hi everyone,
So I’ve been so stressed with senior year that I haven’t had the time to study for my subject tests. I’m conflicted on whether I should/should not rescind my subject tests scores (I’m taking them tomorrow).
I’m going to take the physics and math 2 subject tests and I’m applying to be an mechanical engineer major at UC Berkeley, Cal Poly SLO, UCSD, and other UCs. Note that my SATs and GPA are solid. However, I doubt I will even get above a 650 on either.

Should I rescind my scores or keep/send them, even if there is a high chance they will be bad?

Take the subject tests. I know UC Berkeley requires you to take two subject tests so you pretty much have no choice but to take it now or next month.

The UCs do not require any subject tests but some, like Berkeley, recommend two for certain applicants such as those applying for engineering. Thus, partuicularly for engineering and Berkeley, you should have them to submit if scores are good. If they are really bad (and 650 is not bad), you can just not send them.

The Cal States and Cal Poly’s, including Cal Poly SLO, neither require nor use subject tests for admisison unless they are being submitted to meet an admissions requirement, e.g., you can submit subject test scores to meet certain a-g course requirements if you have not taken a needed course in high school.