Ms Farrington and her group made their way back down the mountain on Sunday.
In the dining hall of a quake-damaged tea house in the village of Tengboche she met the New Zealand group led by Peter Hillary - son of the late Sir Edmund Hillary.
She said the Hillary group were happy to meet another Kiwi and, after sharing stories and videos of what they had all been through, they slept the night on mattresses on the floor, "like a slumber party".
But the group woke at 6am the next morning to screams, after it was discovered a member of the Hillary group - Greg Kay - had died of a heart attack in his sleep.
Ms Farrington said she immediately heard them screaming for one of their group, who she presumed was a doctor.
"He started giving one of the group CPR, he was still warm but they could do nothing for him. It was so heartbreaking for our group and we left with our heads down."
She said it was "incredibly horrific" as there had been a sense of camaraderie between the two groups the night before.
The next two days were spent walking through villages devastated by the earthquake.
Ms Farrington said the path which used to serve as a tourist highway was destroyed and in places the group had to climb well above it to walk safely.
"There are lots of rope bridges we have to cross and they make noises and they shake and the whole group is just terrified of getting across them.
"Every time we hear a loud noise, or somebody scream, we just jump up because we think there's going to be another quake. Our guides were petrified about the rock falls."
Last night, Ms Farrington said Lukla was overcrowded as there had not been any flights out yet due to bad weather. This was a shock to the system after the "ghost towns" she had witnessed coming down the mountain.
"Buildings have just completely fallen down and there's no smoke, there's no children, there's none of the people selling stuff like there was on the way up and it's really quite scary.
"On the way up there were people in the fields, there were people with the animals - now there's no animals, there's no people. There's no one laughing or saying hello as you go past."
She said the village of Pheriche - home to nearest medical facility - was flattened when they reached it on Monday, full of people not knowing what to do, with helicopters landing and taking people out.
Ms Farrington was waiting in Lukla for the next flight to Kathmandu, where she hoped she could do something to help.
She had been living and volunteering in the Nepalese capital since January, and was "terrified" for her friends and the women she taught there. She said she had heard they were all fine, but some had lost their houses.
The next step would be getting on a flight to New Zealand via Kuala Lumpur, she said, but she did not think she would be able to fly out until May 5.
She said the group were "very jumpy" and could not wait to leave.
"Until I am at sea level at home, I'm not going to be happy - it is honestly terrifying."
