more foolproofing.

code/__DEFINES/obj_flags.dm

@@ -10,6 +10,7 @@
 #define UNIQUE_RENAME			(1<<6) // can you customize the description/name of the thing?
 #define USES_TGUI				(1<<7)	//put on things that use tgui on ui_interact instead of custom/old UI.
 #define FROZEN					(1<<8)
+#define SHOVABLE_ONTO			(1<<9) //called on turf.shove_act() to consider whether an object should have a niche effect (defined in their own shove_act()) when someone is pushed onto it, or do a sanity CanPass() check.
 
 // If you add new ones, be sure to add them to /obj/Initialize as well for complete mapping support
 

code/game/atoms.dm

@@ -235,6 +235,7 @@
 	SEND_SIGNAL(src, COMSIG_ATOM_BULLET_ACT, P, def_zone)
 	. = P.on_hit(src, 0, def_zone)
 
+//used on altdisarm() for special interactions between the shoved victim (target) and the src, with user being the one shoving the target on it.
 /atom/proc/shove_act(mob/living/target, mob/living/user)
 	return FALSE
 

code/game/objects/structures/tables_racks.dm

@@ -21,6 +21,7 @@
 	anchored = TRUE
 	layer = TABLE_LAYER
 	climbable = TRUE
+	obj_flags = CAN_BE_HIT|SHOVABLE_ONTO
 	pass_flags = LETPASSTHROW //You can throw objects over this, despite it's density.")
 	var/frame = /obj/structure/table_frame
 	var/framestack = /obj/item/stack/rods
@@ -141,7 +142,7 @@
 		target.Knockdown(SHOVE_KNOCKDOWN_TABLE)
 	user.visible_message("<span class='danger'>[user.name] shoves [target.name] onto \the [src]!</span>",
 		"<span class='danger'>You shove [target.name] onto \the [src]!</span>", null, COMBAT_MESSAGE_RANGE)
-	target.throw_at(src, 1, 1, null, FALSE) //1 speed throws with no spin are basically just forcemoves with a hard collision check
+	target.forceMove(src.loc)
 	log_combat(user, target, "shoved", "onto [src] (table)")
 	return TRUE
 

code/game/turfs/turf.dm

@@ -382,10 +382,17 @@
 		if(ismob(A) || .)
 			A.ratvar_act()
 
-/turf/shove_act(mob/living/target, mob/living/user)
+//called on /datum/species/proc/altdisarm()
+/turf/shove_act(mob/living/target, mob/living/user, pre_act = FALSE)
+	var/list/possibilities
 	for(var/obj/O in contents)
-		if(O.shove_act(target, user))
-			return TRUE
+		if(CHECK_BITFIELD(O.obj_flags, SHOVABLE_ONTO))
+			LAZYADD(possibilities)
+		else if(!O.CanPass(target, src))
+			return FALSE
+	if(possibilities)
+		var/obj/O = pick(possibilities)
+		return O.shove_act(target, user)
 	return FALSE
 
 /turf/proc/get_smooth_underlay_icon(mutable_appearance/underlay_appearance, turf/asking_turf, adjacency_dir)

code/modules/recycling/disposal/bin.dm

@@ -141,16 +141,7 @@
 		if(!pushing)
 			to_chat(user, "<span class='warning'>[target] doesn't fit inside [src]!</span>")
 		return FALSE
-
-/obj/machinery/disposal/bin/shove_act(mob/living/target, mob/living/user)
-	if(can_stuff_mob_in(target, user, TRUE))
-		target.Knockdown(SHOVE_KNOCKDOWN_SOLID)
-		target.forceMove(src)
-		user.visible_message("<span class='danger'>[user.name] shoves [target.name] into \the [src]!</span>",
-			"<span class='danger'>You shove [target.name] into \the [src]!</span>", null, COMBAT_MESSAGE_RANGE)
-		log_combat(user, target, "shoved", "into [src] (disposal bin)")
-		return TRUE
-	return FALSE
+	return TRUE
 
 /obj/machinery/disposal/relaymove(mob/user)
 	attempt_escape(user)
@@ -280,6 +271,7 @@
 	desc = "A pneumatic waste disposal unit."
 	icon_state = "disposal"
 	var/datum/oracle_ui/themed/nano/ui
+	obj_flags = CAN_BE_HIT | USES_TGUI | SHOVABLE_ONTO
 
 /obj/machinery/disposal/bin/Initialize(mapload, obj/structure/disposalconstruct/make_from)
 	. = ..()
@@ -375,6 +367,17 @@
 	else
 		return ..()
 
+/obj/machinery/disposal/bin/shove_act(mob/living/target, mob/living/user)
+	if(can_stuff_mob_in(target, user, TRUE))
+		target.Knockdown(SHOVE_KNOCKDOWN_SOLID)
+		target.forceMove(src)
+		user.visible_message("<span class='danger'>[user.name] shoves [target.name] into \the [src]!</span>",
+			"<span class='danger'>You shove [target.name] into \the [src]!</span>", null, COMBAT_MESSAGE_RANGE)
+		log_combat(user, target, "shoved", "into [src] (disposal bin)")
+		return TRUE
+	return FALSE
+
+
 /obj/machinery/disposal/bin/flush()
 	..()
 	full_pressure = FALSE