Everyone's A Wally: Routine at F54F

F54F: Room logic : The Cave

If the pipe is not patched and the gas mask is not carried, start dropping endurance immediately as the room is full of gas!
F54F	LD A,($BD7D)	Is the pipe in the room?
F552	CP $1D	Is the pipe in the room?
F554	JR NZ,$F55C	Jump forward if it isn't.
F556	LD A,$05	Is the pipe patched?
F558	CALL $EC1D	Is the pipe patched?
F55B	RET NZ	Return if it is.
The pipe is not patched. See if the player has the gas mask.
F55C	LD A,$14	Is the first item carried the gas mask?
F55E	CP (IY+$50)	Is the first item carried the gas mask?
F561	RET Z	Return if so.
F562	CP (IY+$55)	Is the second item carried the gas mask?
F565	RET Z	Is the second item carried the gas mask?
The pipe is not patched and the player does not have the gas mask. Start dropping endurance as they choke to death - oh dear.
F566	LD A,$04	Drop endurance by 6 each frame.
F568	LD ($F26E),A	Drop endurance by 6 each frame.
F56B	CALL $E33F	Mark an immediate collision to drop endurance.
F56E	JP $ED13	Otherwise, the logic is the same as the laboratory.