O’Keefe glances toward the floor and something in his scent changes. Tikki stops in mid-step, freezes. O’Keefe glances toward her left foot, now extended out before her. Just the tip of her shoe touches the floor. She presses downward with the tip of that shoe, just a little, then a little more. Abruptly, the entire section of flooring between her and O’Keefe falls away and crashes into the next level down.