That was understandable given that a round of 69 meant Knox was one of the elite quintet, but the Florida-based Scot was also determined to enjoy every minute of his major championship debut.
"It's mayhem here, especially with the weather and the transportation," Knox, 27, said, a reference to yesterday's two weather delays totalling more than four hours and the compact tournament site which means the range is on Merion's other course.
"It's unbelievable (but) it's as good as I would have ever hoped. I'm thrilled. I didn't really know what to expect my first major, but I knew I was capable of having a nice round and made some nice putts and hung in there. It's hard though.
"If you get on the wrong side of the hole, you're in big trouble. I was lucky enough to leave myself some makeable putts today [Friday], but it's going to be a struggle though.
"It's tough, but I'm definitely not in a position to complain. My first major, I'm just thrilled to be here and so you won't hear any complaining out of me.
"You always get a bit of nerves looking at a leaderboard and if I continue playing well the nerves will come in, but that's what we live for. I feel like I bring my best golf out when I have that feeling."
Knox, who won more than half a million dollars on the PGA Tour last year, added: "I moved to the States to go to college in 2004 and stayed here since in Jacksonville, Florida.
"I miss Scotland and the UK obviously but it is easy to live in Jacksonville. My parents live there also and my sister is in Glasgow. She is jealous sometimes of us living here but she has a nice job (at a local radio station). I've got a good crowd with me this week - my parents, my coach and a few people supporting me so it is nice."
Knox later added a second round of 75 to finish four over par at halfway, comfortably inside the cut.
"It's not often you flush it and shoot five over," he said.
"It was as tough a course as I've ever played. This morning I played nice and holed some nice putts and this afternoon I holed nothing.
"Then once some bad things happen, you get in the rough with a bad lie and you three putt. It is very difficult. I'm trying hard not to be mad at myself for shooting five over because I feel like I played pretty good.
"At one point I looked up and there was one person under par. You are so used to being under par and then when you are over par and it's still pretty good it is tough on your mind. I didn't get down on myself because if you do you can train wreck and end up missing the cut, so I'm proud of myself."