Gail O'Rorke, 43, of Kilclare Gardens, has denied assisting the suicide of Bernadette Forde on 6 June 2011.
Ms Forde died at her home in Dublin on 6 June 2011 after being denied travel to a clinic in Switzerland.
Ms O'Rorke told police it was agreed that another friend of the deceased, Mary Lundy, would be present.
The deceased was diagnosed in 2001 with progressive multiple sclerosis and her condition was compounded by a car accident in 2008 that left her using a wheelchair.
In the police interviews, Ms O Rorke said Ms Forde had arranged for her to stay in a hotel in County Kilkenny so she would be out of the way and not be implicated in the suicide.
She said after Ms Forde's death, Ms Lundy had told her what had happened at Ms Forde's home on the evening of 5 June 2011 when she took a lethal dose of medication bought on the internet.
She said Ms Lundy had sobbed and told her it was the hardest thing she had ever done. She told her she had left the house when Ms Forde was close to death.
Ms O'Rorke told police that she and other family members and friends knew about Ms Forde's plan.
Ms Forde had received a number of visitors on the morning of 5 June and it was known that she planned to take a lethal dose of medication later that day, she said.
In her interviews after Ms Forde's death Ms O'Rorke said she, Ms Forde and Ms Lundy had "sobbed" after she broke the news to Ms Forde that police had intervened to prevent her travelling to Zurich to avail of the services of the organisation Dignitas.
Ms O'Rorke told police that she was personally relieved, but that relief later turned to guilt because her friend's life was falling apart.
After this, she said Ms Lundy researched other options for Ms Forde.
"I took a step back and Mary took a step forward."
She said she did make a money transfer to Mexico but was unaware what it was for the medication that Ms Forde later used to take her life with. She said she only later found out what the package contained.
The prosecution evidence in the case has now ended.
The case is expected to last for another week.

The rape investigation was launched after the 21-year-old woman was attacked in Union Terrace Gardens in the early hours of 28 January.
Crimestoppers has offered the reward of up to £5,000 for information that leads to conviction in the case.
The charity stressed the reward would only be paid if information was passed to Crimestoppers directly.
Angela Parker, the Crimestoppers national manager for Scotland, said: "This attack was on a young woman in the heart of Aberdeen.
"We are now offering a substantial reward for anyone with information to contact Crimestoppers anonymously.
"By contacting Crimestoppers, via the phone (0800 555 111) or our anonymous online form, we don't ask for any personal details, you won't have to speak to the police, and you won't have to go to court. Just tell us what you know, not who you are."

Marc Martin, 22, and Matt Preece, 21, died after the BMW crashed in High Beeches Lane, Handcross, West Sussex, in December 2014.
Mr Martin, from Haywards Heath, and Mr Preece, of Lindfield, were both sitting in the back of the BMW.
Kyle Witney, 21, of Lindfield had previously admitted two counts of causing death by dangerous driving.
Witney has been jailed for six years at Lewes Crown Court.
The court heard Witney had been smoking cannabis and had gone out to get more drugs when the crash happened.
His girlfriend said at the time of the crash he had been showing off in front of his friends "trying to be smart".
The jury was told Witney had said immediately after the crash: "Oh my God, what have I done? I hope I haven't killed my friends."
He told paramedics he had been driving at 100mph.
Mr Martin and Mr Preece were taken to hospital after the crash but died from their injuries.
A 16-year-old girl who was a front-seat passenger in the BMW was also treated in hospital for minor injuries.
Witney had been left the BMW by his grandfather three months before the crash, the court was told.
A Dublin woman on trial for assisting a suicide told police she was not present when her friend took a lethal dose of medication, but another friend was.
[NEXT_CONCEPT]
A £5,000 reward has been offered for information after a young woman was raped in Aberdeen earlier this year.
[NEXT_CONCEPT]
A man has been jailed after two of his friends died when his car hit a tree and flipped onto its roof.