With St. Louis driving into Detroit territory late in a tie game, a broken play on second down saw Rams QB Sam Bradford scramble to the right side. With Detroit down to their final timeout, Bradford smartly slid rather than run out of bounds, to keep the clock going. There was 2:38 left, so the Rams could just run it down to the two-minute warning. Then they would call a running play, forcing the Lions to use their final timeout, and kick a field goal.
That's not what happened.
There was confusion about whether Bradford had slid inbounds, and line judge Shannon Eastin didn't immediately signal either way. The clock operator stopped the clock of his own accord.