Okay so I saw this movie on TV around 2006. It was in color and in English.
I only vividly remember one scene.
So the main character, who was a man, goes into a building to investigate what’s happening to people because they mysteriously keep disappearing. I believe aliens were disguised as humans and were secretly running things and the main character caught on and was investigating. The main character goes to the basement where there is a clinic to treat people. There was a black man running the desk and there was a lot of time between patients being called. The main character’s name was either called or he fought his way to get behind the desk and go deeper into the clinic. After he got inside, he was in a bubble walkway tube type thing where he saw people dressed in white biohazard suits dismembering people and performing experiments on people. He was supposed to be unconscious so the people working there try and kill him but he proceeds to kill the people working. The enemy, a white woman, gets a notification that something is happening in the clinic and orders the building shut down. The main character knocks out one of the bad guys and trades uniforms with him, I believe it was a janitor/cleaning uniform, and walks out of the building with a hat on and his head down while the bad guys were looking for him.