After you have finished hacking the door, it leads to a small outside area. The voice will then tell you they have found your signal and a small cutscene will play of a Secur Tech vehicle behind parked up above you. But there is no way to reach it from where you are.
What you need to do is go back inside and crawl back through the vents. Head back inside the first vent, and follow the linear path until you are above the room you were just in. To your left is a hole in which you will end up back in that very same room if you go that way. Instead, you need to go right and then right again.
You'll see a vent shaft that you may have seen on your journey down to where you learn how to hack. It can now be hacked open. Input the directional arrows on the D-Pad or arrow keys if playing on a keyboard, and the vent shaft shall open, allowing you to go inside. Follow the vent, and it'll lead to where the Sucur Tech vehicle is waiting for you.
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