Need advice. If swallow by accident?

Will the temporary crown fall off? Or what if we swallow by accident with food? Is temporary crown is a small top portion on the tooth or the complete tooth itself is temp crown? I had a root canal on lower first molar #46 7 weeks back. i went back to dentist today to get core buildup,temporary crown. They put a temporary crown on it and said it might fall off. Asked me to come back to them if it falls off, they will put it back.staff just kept the temp crown and she told me to bite on cotton. Didn't fix it hard or cement it.i see tooth color is different now. I don't know the cusp part which I am seeing above the gum is all the temporary crown or it has any portion of my tooth too? permanent crown is after 3 weeks. does brushing makes temp crown fall off? how to know which part is temp crown? I see that tooth color is different now. I don't know which part of cusp is temp crown. whole cusp which we see above gum is temporary crown or it has original tooth?what if swallow by accident?