One cannot be in two places at once
can't be in two places at once
To be unable to exist in two or more places or do two or more things simultaneously. I don't know what more the boss wants me to do—I can't be in two places at once! I told you already, I'll come help you in a minute, sweetie. I'm cooking dinner, I can't be in two places at once.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
One cannot be in two places at once.
Prov. You cannot be in more than one place or do more than one thing at the same time. Child: Mom! Mom! Come help me wash my hair! Mother: Just a minute! I'm putting clean sheets on your bed right now, and I can't be in two places at once.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.