My son tested negative on the rapid test. Two days later he took the slow test and tested positive. His gf tested negative twice before testing positive.
My wife, daughter and I all took the slow test simultaneously (well, in a <15 minute window), and even then, I would not have gone back to help out with my 90 y/o Mom unless all 3 of us tested negative.
Being quarantined for almost 4 full days was a pain in the rear & cost us and Mom serious bucks (more sitter’s $$), but Mom’s life is worth a lot more.