Corrected entry: The T-Virus escapes through the air vent and spreads throughout the entire building, so the air vents must go all over. Later water floods the labs, all of which have air vents, so the rooms shouldn't have filled with water, it should have poured through the air vents and spread throughout the building.
Hamax
7th May 2003
Correction: The red queen could have sealed of the ventilation system in that room when it detected the broken virus sample.
Hamax