"That is an excellent question." He vanishes with a soft crack, then reappears with a woman who looks to be of mixed Asian and African heritage. "I apologize for taking you away from your work, Ms. Wang," he tells her, "but I need to inform the senior university staff of a matter of some but not immediately critical urgency. I need you and whichever assistants you select to find the soonest time available to call a meeting. Interrupting classes is fine but disrupting volatile experiments is unnecessary."
"And you brought me here instead of telling me this in my office because it's important for Miss Zavier and this young woman to know, for some reason?" she asks, glancing at them.
"Their part in this will be explained at the meeting."
He puts her back and returns.