A junior doctor said a strike was "necessary to safeguard" the future of the NHS after an "exodus" of medics.
Thousands of junior doctors in England have started a three-day strike.
Dr Annie Bown, who works at Arrowe Park Hospital in Wirral, said junior doctors had a 26% "real terms pay cut" since 2008 and feared in years to come there would be no doctors for A&E patients.
The government said the 35% pay rise junior doctors were asking for was "completely unaffordable".
The British Medical Association (BMA) members walkout is the biggest by doctors in the history of the NHS.
The union said a 35% pay rise made "perfect sense".
Dr Bown, a first year doctor and chair of the Mersey junior doctor committee, explained she joined the picket line because of an "exodus of doctors" leaving the NHS as "the pay is not attractive anymore" which was impacting on patient care.
"We're seeing longer waiting lists and... patients on trolleys in corridors a lot more frequently and we feel like if things don't change this is only going to get worse."
She added: "We wouldn't be on strike if we didn't feel it was necessary to safeguard the future of the NHS and to make sure junior doctors are being paid what they are worth."
When patients become unwell in hospital, including if their heart stops, she said she would be "the first person nurses would call" to go assess and start treating them - while she was on £14.09 per hour.
"I feel scared for patients in the future," she said, adding she feared in 10 years' time there would be no doctors to see patients in A&E departments.
While she "loved working for the NHS", she said it was "difficult not to be tempted" by adverts for jobs abroad where she "could be paid four times as much".
Alireza Esfandiari, an orthopaedic registrar and executive member for the Mersey junior doctor committee, said: "Morale is at a real all-time low.
"We are all being asked to cover more shifts, carry more bleeps [and] cover more patients than we really should and it is all because of this exodus of junior doctors."
He said union members want pay to be restored to the levels of 2008 in real terms so junior doctors currently on £14 an hour get £19 an hour.
"The NHS is still getting excellent value for money out of its junior doctors," he said.
He said while emergency care was being provided by a consultant and specialist colleagues elective care has been cancelled.
"I'm sorry to those patients but the reality is... there will come a stage in 10 years' time when there's no doctors to see you when you go to the emergency department and that's what we're trying to address."
Health Secretary Steve Barclay said earlier it was "incredibly disappointing" the BMA declined his offer to enter formal pay negotiations "on the condition strikes are paused".
"I want to find a fair settlement which recognises the crucial role of junior doctors and the wider economic pressures facing the UK," he said.
He added he had been working closely with NHS England on contingency plans to protect patient safety during strikes - prioritising emergency, urgent and critical care - but "there will inevitably be some disruption for patients".
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