A paramedic delayed entering a pub to help a dying woman because she felt intimidated, according to witnesses.
Melissa Procter-Blaine, 32, collapsed at The Crown Inn, Spondon, Derby, on 12 July and later died in hospital from a blood clot on her lung.
Onlookers said the first responder did not enter the pub for 10 minutes.
East Midlands Ambulance Service, which is investigating, said the paramedic felt "the atmosphere was tense and intimidating".
Emas is conducting an internal inquiry and the coroner will begin a separate investigation following complaints over Miss Procter-Blaine's treatment.
'Drinker gave CPR'
Pub manager Kevin Pearson, 35, said: "The paramedic was not willing to come up to the pub.
"I banged on the window of the car and she said 'I'm not going in there on my own'.
"I said we needed her to help and she said 'can you guarantee my safety?'.
"She said 'OK, then I will go on your word' and she came up. She said it was an intimidating atmosphere."
In the meantime Mr Pearson said a customer was giving CPR to Miss Procter-Blaine, guided by ambulance call centre staff over the phone.
Michelle Doherty, a friend of Miss Procter-Blaine, said: "She [the paramedic] said she was not authorised to go into the pub.
"I said 'you need to help Melissa, she's dying'.
"It's her job to come and save people's lives."
Miss Procter-Blaine's stepfather, John Page, 59, also witnessed the incident. He is now caring for her three children, aged 14, nine and four.
He said: "The paramedic was an utter disgrace and deserves to be struck off.
"She stood there and made every excuse in the book. She must have stood there for a good 10 minutes refusing to help."
Emas officials said the first responder had arrived six minutes after the 999 call at 2309 BST, followed by an ambulance 10 minutes after the call.
They said Ms Procter-Blaine arrived at Derby City Hospital at 2357 BST, where she died from the blood clot, which had formed after a knee operation.
A spokesman said: "Highly skilled crews were dispatched in a fast response vehicle and ambulance.
"Our solo responder took the emergency kit from her vehicle and entered the premises where the atmosphere was tense and intimidating.
"The coroner will be investigating this case, so it is not appropriate for us to make further comment at this stage."