Your setup works well for singleplayer but not for multiplayer. The button for door1 and door2 can be pressed by seperate players, which then opens both doors. Now that both are open and func_door can only TOGGLE, your airlock is broken forever. You would have to create a eleborate system of multisources to lock the buttons to prevent this. Even then, a player can block the door by crouching under it and the game would never know that the door is now not closed. Which again breaks the entire system.
IMHO, simpler option:
Your setup works well for singleplayer but not for multiplayer. The button for door1 and door2 can be pressed by seperate players, which then opens both doors. Now that both are open and func_door can only TOGGLE, your airlock is broken forever. You would have to create a eleborate system of multisources to lock the buttons to prevent this. Even then, a player can block the door by crouching under it and the game would never know that the door is now not closed. Which again breaks the entire system.