In Remnant: From the Ashes’ Subject 2393, you can’t access the medical bay’s laboratory unless you have the Ward Prime keycard. Unfortunately, it would be best if you did a little backtracking. The first thing you need to do is access the reactor by using the Prime Ward maintenance key, and then you need to destroy the root obstructions. After that, with the reactor on, you need to access the correct computer in the medical ward.
The keycard to access the laboratory is inside the medical storage room. You may have attempted to open these doors up shortly after accessing the medical bay on the lower floors. Make your way back to the medical area by going to the right of the computer you turned on to activate the reactor. There’s an obstruction blocking your path, so destroy it.
The next step is to make your way back to the medical bay. Follow the path through the research bay until you unlock a door connecting the research and medical bays. Form there, you need to find the medical chief’s computer. Look for the room that has the medical chief sign in front of it. Interact with the computer in the room to open the medical storage room.
After that, go to the south side of the medical bay to the medical storage room. You can open up the doors from here, and the red item on the back counter is the Ward Prime keycard. Take it back to the laboratory red panel to use the key, watch it turn green, and open the doors to delve deeper into the abandoned facility.