Go see Mrs Murphy old-fashioned slang euphemism
To relieve oneself in the bathroom.
Pardon me, for a moment. I need to go see Mrs. Murphy.
John's gone see Mrs. Murphy—he should be back very soon.
After going see Mrs. Murphy, John came back with his pale face as if he had seen something spooky.
The verb "go" must be conjugated according to its tense.
This phrase was formed based on the meaning of the noun "Mrs. Murphy".