to anyone that is reading this i worked out that when cracking safes or building a bomb some times u cant move ur action well this cos of the speed your in
some reason the speed ur moving also effects the speed u crack the safe.
so if ur sneaking around then try to crack a safe cos ur sneaking u cant crack the safe as it dont move increase ur speed and u can move it again
no its not normal, you should move keys up and down, or use a wheel mouse up and down, that should be cracking the game... yeah, if you need anything else just write at me... i finished the game twice...
I thought this was a glitch too, but you just need to roll the mousewheel forward a bit so your running speed increases, it allows you to crack the safe, took me a while to figure out too!