Car clipped before plunging into Llyn Clywedog killing family
An impatient driver clipped a car while overtaking, sending it careering into a reservoir where four members of the same family died, a court heard.
Denise Griffith lost her husband, mother and two foster sons in the incident at Llyn Clywedog, near Llanidloes, in April 2011.
Gordon Dyche, 24, denies death by dangerous or careless driving.
Mrs Griffith told Caernarfon Crown Court the family had been on a day out while on holiday in Powys.
Mrs Griffith, 56, said the family had been returning from a day out when she went to pull into a layby near Llyn Clywedog. It was at that moment, she said, that she felt the car being shunted from behind.
"The next thing I knew we were going anti-clockwise," she told the court.
"I saw the rocks, and sky and rocks again, and the water just hit my face.
"I couldn't undo my seat belt at first. I sat in the seat thinking 'how long have I got to live'.
"I was taking water in, I couldn't undo my seatbelt. I thought 'I can't just stay like this'. I just touched my seatbelt and it came undone."
Mrs Griffith and the family dog, Milly, escaped from the car. But, she told the jury: "I just knew the others hadn't made it."
Mrs Griffith lost her husband Emyr, 66, her mother Phyllis Hooper, 84, and Peter Briscome and Liam Govier, both 14 and who had autism.
Mrs Griffith from Pontypridd in south Wales, told the court that as she swam to the side of the lake, a man said: "'I'm really sorry. I was rushing for work'."
Simon Mills, prosecuting, said Mrs Griffith's driving had been described by a witness as "exemplary."
She had indicated to turn right into a lay-by at the side of the reservoir to allow her mother to take photographs, he said.
"The defendant was driving in the same direction as Mrs Griffith but two cars behind her," he added.
"He had become impatient, travelling behind two slower vehicles and tried to overtake both of them. Because he did that he struck Mrs Griffith as she was carrying out her right-hand turn.
"He was responsible for what happened because he took what we say was a dangerous gamble.
"He explained at the scene he had been rushing because he was late for work. He admitted at the scene it was his fault."
But Mr Mills said when formally interviewed by police later that day "he tried to explain away the admissions he made at the scene as having resulted from panic and shock".
Cross-examined by defence barrister Geraint Jones about whether she was sure she had indicated to turn, Mrs Griffith replied: "Positive."
Mr Jones recalled how she got out of the water, she asked someone if she had indicated and she was told that she had.
"Yes," Mrs Griffiths replied. "Can you imagine how I felt at that time? I think to myself 'maybe I just killed my family'. I wanted to make sure I had done everything possible and everything right."
"I know my life has been ruined. It's the most lonely, lonely place to be."
Just before she left the witness box, Judge Niclas Parry said: "Everybody in this room their thoughts are with you."
The trial continues.