diff --git a/code/parse/lua.cpp b/code/parse/lua.cpp
index 7d69edfc4d..91355fd5d1 100644
--- a/code/parse/lua.cpp
+++ b/code/parse/lua.cpp
@@ -4181,6 +4181,7 @@ ADE_FUNC(checkRayCollision, l_Object, "vector Start Point, vector End Point, [bo
 	obj = objh->objp;
 	int flags = 0;
 	int submodel = -1;
+	bool model_started = false;
 
 	switch(obj->type) {
 		case OBJ_SHIP:
@@ -4208,6 +4209,11 @@ ADE_FUNC(checkRayCollision, l_Object, "vector Start Point, vector End Point, [bo
 	if (model_num < 0)
 		return ADE_RETURN_NIL;
 
+	if (obj->type == OBJ_SHIP) {
+		ship_model_start(obj);
+		model_started = true;
+	}
+
 	mc_info hull_check;
 
 	hull_check.model_num = model_num;
@@ -4219,8 +4225,13 @@ ADE_FUNC(checkRayCollision, l_Object, "vector Start Point, vector End Point, [bo
 	hull_check.flags = flags;
 
 	if ( !model_collide(&hull_check) ) {
+		if (model_started)
+			ship_model_stop(obj);
 		return ADE_RETURN_NIL;
 	}
+
+	if (model_started)
+		ship_model_stop(obj);
 	
 	if (local)
 		return ade_set_args(L, "o", l_Vector.Set(hull_check.hit_point));
diff --git a/code/parse/sexp.cpp b/code/parse/sexp.cpp
index d0bfb464df..56e5fa2915 100644
--- a/code/parse/sexp.cpp
+++ b/code/parse/sexp.cpp
@@ -8893,7 +8893,7 @@ void sexp_update_sound_environment(int node)
 	//From sexp help:
 	//{ OP_ADJUST_AUDIO_VOLUME, "adjust-audio-volume\r\n"
 	//	"Adjusts the relative volume of one sound type. Takes 2 or 3 arguments....\r\n"
-	//	"\t1:\tSound Type to adjust, either Master, Music, Voice or Effects\r\n"
+	//	"\t1:\tSound Type to adjust, either Music, Voice or Effects\r\n"
 	//	"\t2:\tPercentage of the users' settings to adjust to, 0 will be silence, 100 means the maximum volume as set by the user\r\n"
 	//	"\t3:\tFade time (optional), time in milliseconds to adjust the volume"},
 
@@ -8921,20 +8921,22 @@ void sexp_adjust_audio_volume(int node)
 
 	if (n > 0) {
 		int option = audio_volume_option_lookup(CTEXT(n));
-		n = CDR(n);
-
-		float target_volume = 1.0f;
-		if (n >= 0) {
-			target_volume = (float)eval_num(n) / 100;
-			CLAMP(target_volume, 0.0f, 1.0f);
+		if (option > 0) {
 			n = CDR(n);
+
+			float target_volume = 1.0f;
+			if (n >= 0) {
+				target_volume = (float)eval_num(n) / 100;
+				CLAMP(target_volume, 0.0f, 1.0f);
+				n = CDR(n);
+			}
+
+			int time = 0;
+			if (n >= 0)
+				time = eval_num(n);
+
+			snd_adjust_audio_volume(option, target_volume, time);
 		}
-
-		int time = 0;
-		if (n >= 0)
-			time = eval_num(n);
-
-		snd_adjust_audio_volume(option, target_volume, time);
 	}
 }
 
diff --git a/code/sound/sound.cpp b/code/sound/sound.cpp
index bbfe0e5d9a..9b23cd23eb 100644
--- a/code/sound/sound.cpp
+++ b/code/sound/sound.cpp
@@ -1396,34 +1396,38 @@ int snd_get_samples_per_measure(char *filename, float num_measures)
 
 void snd_adjust_audio_volume(int type, float percent, int time)
 {
-	Assert( type >= 0 && type < 4 );
+	Assert( type >= 0 && type < 3 );
 	
-	switch (type) {
-	case AAV_MUSIC:
-		aav_data[type].start_volume = aav_music_volume;
-		if (percent < aav_music_volume)
-			aav_data[type].delta = (aav_music_volume - percent) * -1.0f;
-		else
-			aav_data[type].delta = percent - aav_music_volume;
-		break;
-	case AAV_VOICE:
-		aav_data[type].start_volume = aav_voice_volume;
-		if (percent < aav_voice_volume)
-			aav_data[type].delta = (aav_voice_volume - percent) * -1.0f;
-		else
-			aav_data[type].delta = percent - aav_voice_volume;
-		break;
-	case AAV_EFFECTS:
-		aav_data[type].start_volume = aav_effect_volume;
-		if (percent < aav_effect_volume)
-			aav_data[type].delta = (aav_effect_volume - percent) * -1.0f;
-		else
-			aav_data[type].delta = percent - aav_effect_volume;
-		break;
-	}
+	if ( type >= 0 && type < 3 ) {
+		switch (type) {
+		case AAV_MUSIC:
+			aav_data[type].start_volume = aav_music_volume;
+			if (percent < aav_music_volume)
+				aav_data[type].delta = (aav_music_volume - percent) * -1.0f;
+			else
+				aav_data[type].delta = percent - aav_music_volume;
+			break;
+		case AAV_VOICE:
+			aav_data[type].start_volume = aav_voice_volume;
+			if (percent < aav_voice_volume)
+				aav_data[type].delta = (aav_voice_volume - percent) * -1.0f;
+			else
+				aav_data[type].delta = percent - aav_voice_volume;
+			break;
+		case AAV_EFFECTS:
+			aav_data[type].start_volume = aav_effect_volume;
+			if (percent < aav_effect_volume)
+				aav_data[type].delta = (aav_effect_volume - percent) * -1.0f;
+			else
+				aav_data[type].delta = percent - aav_effect_volume;
+			break;
+		default:
+			Int3();
+		}
 
-	aav_data[type].delta_time = time;
-	aav_data[type].start_time = (f2fl(Missiontime) * 1000);	
+		aav_data[type].delta_time = time;
+		aav_data[type].start_time = (f2fl(Missiontime) * 1000);	
+	}
 }
 
 void adjust_volume_on_frame(float* volume_now, aav* data)
diff --git a/code/weapon/beam.cpp b/code/weapon/beam.cpp
index d5543b2ad4..ca3fe976dc 100644
--- a/code/weapon/beam.cpp
+++ b/code/weapon/beam.cpp
@@ -2266,6 +2266,8 @@ int beam_collide_ship(obj_pair *pair)
 	int	valid_hit_occurred = 0;
 	sip = &Ship_info[shipp->ship_info_index];
 	bwi = &Weapon_info[b->weapon_info_index];
+
+	ship_model_start(ship_objp);
 	polymodel *pm = model_get(model_num);
 
 	// get the widest portion of the beam
@@ -2355,6 +2357,7 @@ int beam_collide_ship(obj_pair *pair)
 		valid_hit_occurred = 1;
 	}
 
+	ship_model_stop(ship_objp);
 
 	// if we got a hit
 	if (valid_hit_occurred) {