Next, you have to stabilize the particle accelerator by interacting with two computer terminals, left and right of the Cyclotron.
Upon doing so, a dimensional anomality will take shape in the middle of the apparatus. Interact with it (keep pressing the button) will make you teleport into the Dark Aethereal mirror version of the map. You will remain in this realm for a limited time (2 minutes or so), so hurry up with doing what you must:
Step 1: Localize the Aether Tunnel outside on the surface of the map (it is indicated). Now spend 500 points upon using it, and you will flow to an underground room
Step 2: In the underground room, you will find a spirit-like 'Machine part' of the Pack-a-Punch. Interact with it to pick it up.
Step 3: Now head to the center of the Cyclotron, the very same place where you have entered the portal for the first time. You will find a rough spirit-like structure of the rest of the Pack-a-Punch. Interact with it to add the part, after which you will be teleported back to the normal world and you will now have build a physical Pack-a-Punch.
In case you didn't make it in time and you are teleported back to the normal world before you have succeeded in building the Pack-a-Punch, simply wait till the Anomality reappears again (somewhere else) in the map. This will take about one round. Enter the Dark Aether again and proceed with where you were left.