«إن دخلت هذه الدار وهذه الدار فأنت طالق»
If you enter this house and this other house, a divorce is conditioned upon that.
Waaw combines two entries into one composite condition. Entering only one house does not complete the condition as stated.
The crucial distinction is that both entries are required, but their temporal order is not necessarily fixed by waaw. Treating the first-mentioned house as invariably the first to be entered would add a condition not conveyed by this particle.