Something more about runtime errors.

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

@@ -834,7 +834,7 @@
 	..()
 
 /mob/living/carbon/human/vomit(lost_nutrition = 10, blood = 0, stun = 1, distance = 0, message = 1, toxic = 0)
-	if(blood && (NOBLOOD in dna.species.species_traits))
+	if(blood && dna?.species && (NOBLOOD in dna.species.species_traits))
 		if(message)
 			visible_message("<span class='warning'>[src] dry heaves!</span>", \
 							"<span class='userdanger'>You try to throw up, but there's nothing in your stomach!</span>")

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

@@ -20,7 +20,7 @@
 
 
 /mob/living/carbon/human/proc/checkarmor(obj/item/bodypart/def_zone, d_type)
-	if(!d_type)
+	if(!d_type || !def_zone)
 		return 0
 	var/protection = 0
 	var/list/body_parts = list(head, wear_mask, wear_suit, w_uniform, back, gloves, shoes, belt, s_store, glasses, ears, wear_id, wear_neck) //Everything but pockets. Pockets are l_store and r_store. (if pockets were allowed, putting something armored, gloves or hats for example, would double up on the armor)

code/modules/mob/living/carbon/inventory.dm

@@ -72,7 +72,7 @@
 			put_in_hands(I)
 			update_inv_hands()
 		if(SLOT_IN_BACKPACK)
-			if(!SEND_SIGNAL(back, COMSIG_TRY_STORAGE_INSERT, I, src, TRUE))
+			if(!back || !SEND_SIGNAL(back, COMSIG_TRY_STORAGE_INSERT, I, src, TRUE))
 				not_handled = TRUE
 		else
 			not_handled = TRUE

code/modules/mob/living/simple_animal/bot/bot.dm

@@ -194,10 +194,12 @@
 	if(locked) //First emag application unlocks the bot's interface. Apply a screwdriver to use the emag again.
 		locked = FALSE
 		emagged = 1
-		to_chat(user, "<span class='notice'>You bypass [src]'s controls.</span>")
+		if(user)
+			to_chat(user, "<span class='notice'>You bypass [src]'s controls.</span>")
 		return TRUE
 	if(!open)
-		to_chat(user, "<span class='warning'>You need to open maintenance panel first!</span>")
+		if(user)
+			to_chat(user, "<span class='warning'>You need to open maintenance panel first!</span>")
 		return
 	emagged = 2
 	remote_disabled = 1 //Manually emagging the bot locks out the AI built in panel.
@@ -205,7 +207,8 @@
 	bot_reset()
 	turn_on() //The bot automatically turns on when emagged, unless recently hit with EMP.
 	to_chat(src, "<span class='userdanger'>(#$*#$^^( OVERRIDE DETECTED</span>")
-	log_combat(user, src, "emagged")
+	if(user)
+		log_combat(user, src, "emagged")
 	return TRUE
 
 /mob/living/simple_animal/bot/examine(mob/user)

code/modules/mob/living/simple_animal/bot/mulebot.dm

@@ -123,7 +123,8 @@
 		emagged = TRUE
 	if(!open)
 		locked = !locked
-		to_chat(user, "<span class='notice'>You [locked ? "lock" : "unlock"] [src]'s controls!</span>")
+		if(user)
+			to_chat(user, "<span class='notice'>You [locked ? "lock" : "unlock"] [src]'s controls!</span>")
 	flick("mulebot-emagged", src)
 	playsound(src, "sparks", 100, FALSE)
 
@@ -766,4 +767,3 @@
 
 /obj/machinery/bot_core/mulebot
 	req_access = list(ACCESS_CARGO)
-