The only game I have left early in 50 years of going to anfield was the recent Sunderland game when I left 13 mins before the end leaving early is something I can never fathom especially when it's £60 a game. Mind one time I had to go to the toilet mid half and believe it or not there are people in the inside the stand drinking tea and coffee I will never understand some folk completely barmy but there we are that's the way things are
I was at a friendly against Celtic in 99 or 2000, we won 4 - 1 and I missed every single goal.... had a skinfull before the match and my bladder gave in about a minute before every goal scored!
As for leaving the match early.... I only ever go to mid week matches so I always leave around the 87 / 88 minute mark to get a jump on the ques... I need a good 8 hours sleep minimum and skipping the last couple of a match generally get me home sharpish (although, I stay on if the match is a bit tasty / out for an extra pint if it can't be avoided)