Uncomfortable Silence Puns

We were taking a final in drivers ed and one of the questions was "How long does it take to fall into a stare" and the instructor said, "Wait a minute I have to go stretch" and so he walked outside so we could see him out the window and he proceeded to intentionally trip down the stairs. He walked back inside and said "That should answer that," and everyone sat their uncomfortably until he looked closer at the paper and said, "oh, I thought it asked how long does it take to fall into a stair". Needless to say there was the longest uncomfortable silence, accompanied by a faint cough in the back...