Sure! Bad End 5 is on the operator route, so first you have to select the option "Trust the pilot." when Dex gets into a scuffle with the IG officer off ship. Then, when the operator visits the ship, you have select "Tell him about Dex's injury."
After that, when the ship gets hit with the EMP blast and you encounter the stranger, choose any of these options: "Help me remember.", "Dex needs him.", or "I can't..." and you'll get bad end 5!
Hope that helps :)