They were so stressed that they didn't even know that the stone was already rolled away. Sometimes stress makes us paranoid, no matter how cool you may 'seem' on the outside. See verse 4: "And when they looked, they saw that the stone was rolled away: for it was very great. (Keep your spiritual eyes open and stop feeding that flesh.
How do you miss the fact that the hindrance that you THOUGHT that you had, didn't really exist?
Keep your eyes on Jesus because the flesh will have you off-kilter.