The difficult part begins now since you need to infiltrate the enemy base. First thing to remember is use shortcuts and/or tunnels and move when you absolutely have to in order not to draw any attention. You may be invisible but units such as Sydney or Patch may still detect you and try to take you out. If you notice that some entrances are mined, don't bother going through the mines, you'll just die and throw away 1400 credits for nothing. Try to find another way into the base, time your actions, if the base is occupied with a lot of troops wait until they get out or do something else, then go for it. When in the base, be quick. Try to move near the walls and stay clear of the enemy. Pick a building (WF and PP make perfect targets since you'll hurt the enemy a lot if you take those out) and place the nuke in a spot that will make it hard for them to defuse it and will also you give you the space to defend it. Place your c4 charge near the beacon so that if they get too close trying to defuse it, the c4 will get them instead. Defend the beacon. If all goes well, the explosion will destroy the building, their defensive/offensive capability will be crippled and you'll get a lot of points