From the pictures sent by you, i see a leakage in concrete slab which seep over steel beam.
Possible causes of leakages are as follows;
Slab itself had a crack in it which was not sealed before doing waterproofing. it is clear indication of waterproofing on slab top is damaged / cracked, it allowing water to pass through it which further comes down from slab.
crack in slab might be developed due to heat or during installation of steel beam after casting of slab.
the water only leaks when there is source of water.
If your slab is not top slab where terrace is situated above.
The water might come from flooring of Toilet / Bath to the slab of bed rooms.
When the tile joints have improper grouting, i.e. - joints in tiles not sealed completely.
and if waterproofing top had not sloped correctly or there is chocking or no source to move the water coming below tile to Floor trap drain or spout, this water might flow in bedroom area and cause a leakage from slab( we do waterproofing of slab areas which may directly come in contact of water).
if above is the case, do a rich mortar bedding below a door threshold which will block the water coming from toilet to bedroom area.
clear the spout if its chocked, make a way for water to flow out into floor trap by either making holes in extended pipe from floor trap, or making drain tubes into the finish face of bedding mortar in floor trap area.