I heard somewhere that you're not allowed to walk, stand, or sit, anywhere within 4 Amos of a person Davening Shemoneh Esrei because you're walking through the Shechinah.
Does this have a source? Are there any exceptions to the rule? Say there's a table in between you and the person? What if you're in a rush, and there's no way to get by unless you pass through their 4 Amos?