Fixes heartbeat sounds playing indefinitely in certain cases

code/modules/mob/dead/observer/observer.dm

@@ -249,6 +249,7 @@ Works together with spawning an observer, noted above.
 /mob/proc/ghostize(can_reenter_corpse = 1)
 	if(key)
 		if(!cmptext(copytext(key,1,2),"@")) // Skip aghosts.
+			stop_sound_channel(CHANNEL_HEARTBEAT) //Stop heartbeat sounds because You Are A Ghost Now
 			var/mob/dead/observer/ghost = new(src)	// Transfer safety to observer spawning proc.
 			SStgui.on_transfer(src, ghost) // Transfer NanoUIs.
 			ghost.can_reenter_corpse = can_reenter_corpse

code/modules/mob/living/carbon/human/death.dm

@@ -19,6 +19,10 @@
 /mob/living/carbon/human/death(gibbed)
 	if(stat == DEAD)
 		return
+	stop_sound_channel(CHANNEL_HEARTBEAT)
+	var/obj/item/organ/heart/H = getorganslot("heart")
+	if(H)
+		H.beat = BEAT_NONE
 
 	. = ..()