Griffiths, 64, is now thankfully back working full-time again at the South Yorkshire club having undergone successful heart surgery in September.
He was out running when he initially fell ill and has spoken publicly for the first time about the events of that night.
The Welshman admitted his thoughts did turn to Williams, the Doncaster prop who died aged just 27 after collapsing at a club training session in February.
“Yes, things like that do cross your mind,” Griffiths told The Yorkshire Post in an exclusive interview.
“The goal is just to try and get back (home) and get better again. That was the first thing.
“Step by step, all the way back. Every step you take you’re getting closer to a recovery. But the last bit, up the hill back to my home, it was a bit spooky.
“I run on the town fields but I was on the first corner away from where we live so that was the worst thing – just actually getting back from there.
“It was only 10 minutes away but it took me 40 minutes in the end. I got there eventually.
“I finished up walking up that hill, and – knowing you were in a bit of trouble – it was a bit scary.”
Even then, Griffiths – Wales’ defence coach when they won the 2005 Six Nations Grand Slam – still did not comprehend the seriousness of the issue.
“I jumped in the shower at first and put the water on my back to see if I could loosen it up as a last resort,” said Knights’ director of rugby.
“I thought it might have been a muscle spasm. But I had tingles down my arm as well so I was probably clutching at straws.
“I phoned the doc and he said ‘get down to A&E now’. A friend of mine took me. Seven days later I was out having been angiogrammed, stented... and just waking up every two hours.”
A dual-code Wales international who starred with Llanelli and then St Helens, Griffiths admitted the scare has made him take stock and be more contemplative.
“It does a bit; it does spook you a little, particularly where family is concerned,” added the coach, who returned to Doncaster for a second spell six years ago, leading them to the play-offs for the first time plus maiden Championship and British & Irish Cup finals.
“That’s the biggest thing; you’ve been dealt a bit of a blow but you have got to get yourself up and dust yourself down.
“I was surprised it happened as at that particular time I was probably running as freely as I have done in years. I was getting my second wind and off I’d gone.
“I was in the gym and doing circuits well, lifting (weights) well and felt really, really good.
“But the day before I felt a bit funny. I went to see the doc and it was just something that didn’t feel right. I couldn’t put a finger on it but just didn’t feel myself.
“Yet after I’d been to see the doc I still went and did a workout in the gym. Then on the Friday night I just went for a run and 10 minutes in put the brakes on. I knew there was something amiss.”
One of rugby’s most colourful, passionate characters, Griffiths lives and breathes the sport and has a vast knowledge of both codes.
Among his long list of feats, he was coach of Wales when they almost caused one of the biggest rugby league shocks ever, leading the fabled champions Australia in the 58th minute of a famous, epic World Cup semi-final in 2000.
He had been the most expensive player in the world when moving from Llanelli to St Helens in 1979 and has worked as Great Britain assistant coach as well as at clubs such as London Welsh, Swansea and Worcester.
Asked if he ever wondered if he would get back to coaching after his heart attack his answer is emphatic: “Never.”
The sight of an irate Griffiths throwing his arms around and gesticulating from his viewing position on the balcony behind the Castle Park posts has become a common one for Doncaster supporters over the years.
However, after a staggered return to work, he maintained he is learning to take things easier during pressure game situations.
“I’ve calmed down a lot,” he said, ahead of Saturday’s home game against Nottingham, where victory will confirm a place in the inaugural Championship Cup quarter-finals. “I’m more verbal now rather than gestures. I stopped jumping up and down after I snapped my Achilles anyway.
“That was after we beat Leeds (Yorkshire Carnegie) here with 13 men at the end. Once Michael Heaney kicked the ball out, I jumped up in the air and when I came down it just went ‘bang’.
“It was worse than my heart attack as it’s so debilitating. It was six weeks in the boot and putting the wedges lower and lower. Again you just get on with it. You can’t moan about it; it is what it is.
“Now, with the heart, I have to watch my diet. You have to lower your fat intake, the saturated fats. My cholesterol is down to two so that’s very good.
“I’m going to my third cardiac rehab session on Wednesday and that will probably be my last one.
“You get monitored with your blood pressure. I feel okay, touch wood, and I just have to make sure I’m not jumping up and down too much. It’s good to be back. Much better than being sat at home.”