Murray's weakness was his positioning. He consistently stood too far off the man he was marking and didn't get close enough to tackle. If he had the speed of, say, and Andy Dornan, he could have got away with it. But he didn't, and he couldn't.
As someone who stood in the shed, there were many times I was closer to the opponent than he was.
As for John Gardiner - of course as a professional keeper he did occasionally make saves and even have a game or two when he didn't make mistakes. However, his overall performances were littered with poor positioning, inability to take a cross and 'spills'.