>would it be unwise to take a loan for 7k of money I've set aside for retirement?

Yes it is.

Taking a 401k loan means the funds are out of the market until repaid, so hurts your growth and plan balance over the long run.

Short term, in the unlikely event you lose your job, the entire loan could become due immediately, and would be taxable + 10% penalty if not paid. And since a loan has no withholding when originally taken, that's a possibly large tax bill.

401ks also have strict rules about loan eligibility: you can only take max 50% of your balance up to $50k, with a 12 month look-back rule on that limit. So if you took a loan now and then had a truly dire emergency, you'd be possibly unable to take another loan at that time.