The scenes she filmed on her phone as she left give an insight into the violence sweeping through the Sudanese capital since a power struggle between the army and the RSF paramilitary group escalated into all out conflict on April 15.
The clashes have killed at least 512 people.
"I contacted the British embassy. I would say all day, every day for a week to see when we would be able to be evacuated," she told Reuters from Cairo.
"No solid plan was given to us a week later, which is when I decided to take matters into my own hands because I ran out of water," she said, describing cowering at home with dwindling provisions as gunfire, shelling and air strikes raged outside.
Britain, with an estimated 4,000 nationals in Sudan, began airlift evacuations on Tuesday to Cyprus. It has been criticised for lagging other European countries in flying out citizens.
Ahmed said she and others mobilised to plan their escape, after hearing some people were heading north by bus to Egypt.
"We hired a bus. There were about 50 of us," she said.
Moving through the war zone was the most frightening part.
"On a number of occasions we drove past tanks and heavily armed humans. That just terrified us because we had heard reports of buses being stopped and robbed and people being shot... That left me truly shaken. But we didn't have a choice."
Although feeling absolutely petrified, externally she was remarkably composed and calm, Ahmed said.
"I suppose you know what they say - God takes the wheel."
Her journey from Khartoum to the Egyptian border took 12 hours but then it took another day and a half to enter Egypt because of the queues.
She plans on leaving Egypt after taking a few days to recover from her ordeal.
"My heart is still in Sudan. I can't stop thinking about the people that are stuck there, who don't have the means to get out. I really hope and pray that evacuations are now in order. That there is support, that there is assistance."
(Writing by Alexandra Hudson; Editing by Alex Richardson)
By Anna Magdalena Lubowicka
