Suspending all internal disputes in the presence of an external foe is a common family/tribal behavior, and not exclusively Indian.
Even if she was in the middle of punching me, if you started walloping my wife with an umbrella, my frame of mind would immediately shift from wherever it was to "my wife is being attacked by an umbrella-wielding stranger."
>>qq66+(OP)
You're right, and I wasn't saying it was a strictly Indian behaviour. But I must say that I expected relief from her, not attack. I only hit the dude once - to make him stop.