Artak is of course right. However, when dealing with vehicles like this I prefer to use
(not canMove BMP1) and (not canFire BMP1) etc
rather than not alive. This means your condition will become true when the BMP ceases to be a functional unit, rather than when it is completely destroyed. Sometimes you can get vehicles which look dead, have no crew and can't move or fire but aren't technically "not alive", so the mission hangs up until somebody puts another LAW into it.