u/MtAlimanjaro

Any thoughts on the severity of this water ingress next to the balcony sliding door? The salt deposits on the tiling make me think failed membrane but I don't know much about this stuff.. Agent is minimising the problem as it just needs patching the skirting board and carpet but I'm worried there could be mould inside the walls and the balc would need a new membrane (it's a very big balc so that will cost a bomb).. I should probably walk away right? Or should I be a gambler? Maybe it's not that bad?