A multistage connector assembly for a lumen decontamination system is provided. The assembly includes a main body, a multistage body, a multistage barrier, a connector, and one or more biasing members. The assembly includes a multistage barrier movable in the fluid passageway between a fully closed position in which each stage of the multistage barrier is in a closed position to each independently block flow in the fluid passageway and a fully open position in which each stage is in an open position to allow flow within the fluid passageway. The connector is configured to engage the multistage barrier when coupled to the main body to sequentially open each stage of the multistage barrier to enable flow through the fluid passageway. The biasing member(s) are configured to urge each stage of the multistage barrier towards a closed position that blocks flow in the fluid passageway.