Whitney had to keep going. The second substructure had sub-parts. She worked through them: one reduced, then a second reduced.
Then she made a sign error.
She didn't catch it for two lines. When she did catch it, she froze, her shoulders dropping just slightly. She erased two lines and rewrote them. A small murmur went through the audience again. Walsh leaned forward, his face tight with something that almost looked like hope.
Whitney took a breath and kept going. She finished the second substructure and drew a box around it. It was rougher than the first, but it was done.
She moved to the third board. The clock on the junior faculty member's phone read eleven minutes. The audience had been silent for the last four: they were not bored anymore, they were not impatient—they were watching a person work.
Whitney looked at the third substructure. She started to write. She wrote two lines, and then she stopped.
Her chalk was three inches from the board. It did not move. She stared at the second line. She did not write anything else. She did not move.
For a long ten seconds, the room watched her not move. Walsh, who had been smiling, stopped smiling. In the third row, a phone slipped slightly in someone's hand; they caught it without looking. They were not breathing.
Something had happened on that board. Something Whitney could see. Something Walsh could see now, too. But no one in the audience knew what it was.
Sullivan stood up halfway, then sat back down. Dr. Whitmore, in the back, leaned forward in her seat and closed the journal in her lap.
Slowly, Whitney lowered the chalk. She turned away from the board and walked to the side of the lecture hall. She did not say anything. She did not look at Walsh; she did not look at the equation. She put her hand against the wood paneling of the side wall, closed her eyes, and for five seconds, did not move.
In the front row, Walsh sat very still. His right hand, the one that had been trembling earlier, was now completely still. He looked at the third substructure on the board. His face went pale.
What had Whitney just seen on that blackboard? And what was Walsh now realizing twelve minutes too late?
Dr. Whitmore stood up. She did not move toward the front; she did not raise her voice. She simply stood in the back row holding the journal in her right hand.