Calling for help is stupid because most likely they will point camera into the room to see what is wrong, then notice there is an intruder after coming down.
Chat would be useful, but you only can selecto ne option, and most likely the person you are chatting with suspects something is wrong.
I am stuck between open door and power down. I don't know if powering down will power down the whole building or just the terminal, if the whole building was powered down the auto defenses that may exist.
The door may have large numbers of enemies on the other side.