The Assistant Manager Keycard is vital for opening all previously locked doors in the Black Ant Lab, but obtaining such a card requires defeating a fairly tough enemy. However, you will need to brave the boss fight if you want to complete the Black Ant Lab quest line. Here's how you can do it.
How to find the Assistant Manager in Grounded
You must first enter the Observation Chamber in the Black Ant Lab to find the Assistant Manager. To do this, you'll need to unlock the glass window blocking you from the observation chamber. In the room you're in, look for a button along the back by the cliff edge.
After you press the button, the window should reveal a sizable crack. Use a bomb to create a hole you can move through. For the boss fight to start, you'll need to use the console in the room, but know that once the fight starts, you'll be locked in the room with TAYZ.Ts and the Assistant Manager.
How to beat the Assistant Manager
The Assistant Manager's fight lasts for three phases, and they will summon other fighters to assist them throughout the battle. Keep up your stamina and health and focus on both causing smashing damage and utilizing quicker weapons. Other than that, try to keep the number of minions under control because they can become overwhelming quickly.
The Assistant Manager will drop the Key Card after you defeat them. You can claim their access ID immediately after winning.