He was there 20 years ago with a Kilmarnock team trying desperately to stay in the Scottish Premier League and watched experienced men like Tommy Burns and George McCluskey affected by nerves far more than they ever were at Celtic.
The fear of losing was far more powerful than the desire to win and Burns, who was Kilmarnock's player-manager on May 15, 1994, could not eat his breakfast at the team hotel before that dramatic final day of the season. McCluskey, who had played against Real Madrid during his time at Celtic, later missed Burns' team talk because he was being sick in the toilets.
Backed by 6000 supporters, Kilmarnock secured the point they needed by recording a 0-0 draw, with the Ayrshire side staying up at the expense of St Johnstone. They have since remained in the top flight for two decades.
Millen - who also played for Hibs during a long career - believes that Kilmarnock owe Burns so much, that they secure the result today which will be enough for the club to avoid the discomfort of competing in a play-off to remain in the top division as a tribute to the man who died six years ago from skin cancer.
"Tommy was an inspirational player-manager for me and the other guys at Kilmarnock," said Millen, who helped Burns drag the Rugby Park team up from the third tier of the Scottish game. "Tommy was such a passionate man. All his emotions, good or bad, were out there for everyone to see. He got the club two promotions but it was vital we stayed up in our first season back: 1993/94.
"That was a 12-team league where three went down. Dundee and Raith Rovers were already relegated and we had to get a point at Easter Road to be safe. We stayed in a hotel in Edinburgh and Tommy could not eat his breakfast on the Saturday morning. He was so nervous.
"At the ground, George McCluskey was busy being sick in the toilet before kick-off. He was hit by the enormity of it all, too. Tommy and George had played in European Cup games and Old Firm matches but they had never been involved in a game where there so much at stake for losing.
"We got the 0-0 we needed and the 6000 Killie fans on the terracing behind the goal gave us amazing backing. They pushed us through. I think all Kilmarnock fans would admit that Tommy did so much for the club. Kilmarnock FC should always be indebted to him because he kept them in the top flight and they have stayed there ever since.
"I was at his funeral in May 2008. It will soon be the sixth anniversary of his death and I think it would be fitting if Kilmarnock stay up as a tribute to him."