Been there....
On my bull elk hunt in Wyoming I drew my bow as the bull entered the opening. At full draw he stopped behind a tree and looked at me or so I thought. I was on one knee at full draw holding it with no shot. The bull stared, the guide screamed on the bugle the bull stared I held my draw......and held, and held and held. The bull actually was looking over my shoulder at the guide behind me about 30 yards. I could tell the bull wasn't locked on me as every now and again he'd look toward me and then turn and look over my shoulder and still I held. I pushed the cam into my knee so I could lock it in...I turned my chin into the string to help try to hold it...I shook....at "forever" the bull stook a step forward, I raised up, locked the bow in and released...the bull went 50 yards and collapsed.
you'll never know if your locked in with your pin until your there. Everyone is different and only you will know when that moment of truth happens. For me, when the bull stepped out, all my muscles resumed form. I was rock steady for a moment...aftet the shot I collapsed in exhaustion sucking wind....I felt like I ran a marathon. The guide/friend snuck up behind me and said "I never thought you'd be able to hold that"...I said I would have held it for hours...laughing....the bull laid out in the timber at 50 yards. It was incredible.