Assure your mother that she's not wasting anyone's time! Also, it's not her job to know if something is an emergency, s it's okay to go the ER and find out everything is fine.
Thank you so much. I begged her to let me take her to the ER last night, it was pretty bad - but she refused - she said she'd "feel stupid" since her oxygen/heart rate go back up to normal in between the bad episodes and she "doesn't want to waste their time." With your advice I think she will listen (she appreciates my asking things here).With her permission I reached out to her regular long-time pulmonologist via her patient portal to ask if she should come in to see him soon. I did mention the low heart rate in that message. Hopefully will hear back soon. If her heart rate goes down that low again I'll remind her of an actual physician's advice (thank you thank you!) and she will listen.