Use the scientist's special skill by the Door Control Console.
Follow the long corridor to the end to find a Grog Machine. Use the special skill on it to find out that it's a hidden method of reaching the laboratory.
Run left, swim through the water and take out the fuse from the Fuse Box on the wall.
Climb the ladder with it and put the fuse into the second box. Head to the left, press the Elevator Call Button and stand on the platform to ride it up.
Climb the ladder to the Lower Blast Door Console and use your special skill on it. Return to the elevator and ride it down to see that the rocket is heating its engines.
Ride up again and head to the right. The door which was blocking the passage up until now will automatically open.
Wait for the laser beam to turn into the other direction and quickly use your special skill on the Laser Control Console. Pick up the Launch Key which the dead scientist left from the floor.
Return with the key to the first room and put it into one of the three Keyholes.
Head back to the right and use the scientist's skill on the Elevator Console on the right to activate the elevator. Ride it down.
Head to the lowest, third floor. There you will find a Wet Floor Sign. Take it and head to the 2nd level.
Find the Tech Lab and place the wet floor sign to the right of the technician. Afterwards use the special skill on the Warhead Loading Console on the right side of the room. The technician will slip and kill himself. Pick up the key lying beside him and put it into the second Keyhole in the first room, by the entrance to the complex.
Head back to the second level but this time go to the right. You should find a big Bulletin Board. Take a closer look at the menu and days of week.
Go to the lower level and head into the cafeteria. Look at the board to find out what's the day of the week. It will vary with each walkthrough. You have to compare the name of the dish on the board with the one on the bulletin board above.
On the right side of the board you will find a Fruit Bowl on the table. Keep reaching for it until you take out bananas. Take them.
Ride the elevator up and head to the right to the Administrator's Terminal. Activate it and look at the sticky notes.
You should already know what day of the week it today, so write down the corresponding code.
Ride down the elevator and go down onto the third floor. In the corridor on the right you will find four Code Entry Buttons. Enter the code corresponding with the current day and afterwards push the Confirm Code Entry. If you have entered the proper code, the passage will open.
Head into the room and take the Knockout Gas.
Go to the 1st level and head maximally to the right. At the end you will find a ventilation system which should be at the moment sucking out air.
Switch to the second character and head to the far right on the highest level of the lab. There you will find the HVAC Control Switch. Use it and quickly switch back to the scientist.
Drop the gas container onto the floor. If you make it in time, you will get rid of the guard and obtain the third key. Of course take it to the first room and put into the Keyhole.
Behind the unconscious guard you will find a room with a Chimp. Give him the bananas and it will start following you. Go to the 2nd level and to the room on the left side.
After you get there, the chimp will jump into the capsule. Head back above, to the place with the three keys.
Turn all three keys with all characters and the rocket will be launched. Afterwards head out of the room to the left, ride down the elevator and go left, along the tour direction.