Though the pacing of the bubble wall does have great comedic potential for holding attention awkwardly, as you're signalling you suddenly want a barrier between you and a coworker. Optional is to also maintain intense eye contact, as they can see the barrier rise between you, initially in their peripheral vision. For the labor-saving eyes-free option, maybe accompany inflation with some milquetoast elevator music.
(If one could move to Google without months of test-prep, someday I'd be happy to share additional perspectives on technology and office dynamics.)