There is no quick temporary solution.

It is bathroom but what is exactly behind the the wall. Is it a sink or toilet flush?

I meant at the most wet spot on the wall. It cannot be all three

Contractor will knock the wall at the most damp location as it is most likely the leak pipe location. Once fixed, will leave it and see it the wall dries up to confirm.

The higher wet point is not necessarily the starting point. The water absorbed up like osmosis. The most damp location is the likely point. Looking at the tile as scale, the height is about sink or toilet flush location I think.