How do you get past level 2 on Resident Evil outbreak

Depending on what character you use, if you are in B7F, you need to go to the liquid disposal room and behind the next door is a zombie,kill him and get the jug on the ground. Now go to the laboratory if you follow it you will come to a computer with a memo on it get the memo and head to the chemical room. Go up the corridor and examine the computer before you do you will need to go to the the last page and get the code. Type the code into the computer. Some draws will shift examine the draw that is open. A chemical will be there mix it with the jug you found earlier. Now find your way to the Duct. There will be a scientist there. Give him a first aid spray and he will give you a shotgun. Continue through the duct and you will find a big plant use the mixed formula and an animatic will be displayed. Go up the ladder. Go through the door and continue a long the corridor. George may link up with you at this time. Follow the corridor but don't turn when you can follow the corridor and a frozen wrench is on the ground. Grab it and go back to the turn and just continue to the break room. walk right and there will be a sink use the wrench. Now go back to the control room. with the door in the middle. on the right is a control panel use the wrench and get the valve.
Now go back the duct and extend the ladder. That's the difficult part. (if your character is on B6F do these actions in reversed order(get the valve first then the chemical).

Fom now on it is easier.