No, youve simply stated that somehow a wall would hinder it, theres no reason why that would be so and if it is, you would have to show why and how...not simply state...
The main facts on the bloodshower is that Kain casts the spell, no particulour target needed so its nothing to do with whom he casts it at or line of sight. Then the blood of all entities nearby get drained towards him...the fact in Samus' case her blood will just fill her suit if it is indeed tight. She will still drop dead.