diff --git a/Source/monster.cpp b/Source/monster.cpp
index 0ab2d955c..6f00178cc 100644
--- a/Source/monster.cpp
+++ b/Source/monster.cpp
@@ -1949,20 +1949,22 @@ void GroupUnity(int i)
 	assert(i >= 0 && i < MAXMONSTERS);
 	auto &monster = Monsters[i];
 
+	if (monster.leaderflag == MonsterRelation::Individual)
+		return;
+
+	assert(monster.leader >= 0);
+
 	auto &leader = Monsters[monster.leader];
-	if (monster.leaderflag != MonsterRelation::Individual) {
-		bool clear = IsLineNotSolid(monster.position.tile, leader.position.future);
-		if (clear || monster.leaderflag != MonsterRelation::Minion) {
-			if (clear
-			    && monster.leaderflag == MonsterRelation::Leader
-			    && monster.position.tile.WalkingDistance(leader.position.future) < 4) {
-				leader.packsize++;
-				monster.leaderflag = MonsterRelation::Minion;
-			}
-		} else {
-			leader.packsize--;
-			monster.leaderflag = MonsterRelation::Leader;
+	if (IsLineNotSolid(monster.position.tile, leader.position.future)) {
+		if (monster.leaderflag == MonsterRelation::Leader
+		    && monster.position.tile.WalkingDistance(leader.position.future) < 4) {
+			// Reunite the separated monster with the pack
+			leader.packsize++;
+			monster.leaderflag = MonsterRelation::Minion;
 		}
+	} else if (monster.leaderflag == MonsterRelation::Minion) {
+		leader.packsize--;
+		monster.leaderflag = MonsterRelation::Leader;
 	}
 
 	if (monster.leaderflag == MonsterRelation::Minion) {
@@ -1970,29 +1972,26 @@ void GroupUnity(int i)
 			leader.position.last = monster.position.tile;
 			leader._msquelch = monster._msquelch - 1;
 		}
-		if (leader._mAi == AI_GARG) {
-			if ((leader._mFlags & MFLAG_ALLOW_SPECIAL) != 0) {
-				leader._mFlags &= ~MFLAG_ALLOW_SPECIAL;
-				leader._mmode = MM_SATTACK;
-			}
+		if (leader._mAi == AI_GARG && (leader._mFlags & MFLAG_ALLOW_SPECIAL) != 0) {
+			leader._mFlags &= ~MFLAG_ALLOW_SPECIAL;
+			leader._mmode = MM_SATTACK;
 		}
-	} else if (monster._uniqtype != 0) {
-		if ((UniqMonst[monster._uniqtype - 1].mUnqAttr & 2) != 0) {
-			for (int j = 0; j < ActiveMonsterCount; j++) {
-				auto &minion = Monsters[ActiveMonsters[j]];
-				if (minion.leaderflag == MonsterRelation::Minion && minion.leader == i) {
-					if (monster._msquelch > minion._msquelch) {
-						minion.position.last = monster.position.tile;
-						minion._msquelch = monster._msquelch - 1;
-					}
-					if (minion._mAi == AI_GARG) {
-						if ((minion._mFlags & MFLAG_ALLOW_SPECIAL) != 0) {
-							minion._mFlags &= ~MFLAG_ALLOW_SPECIAL;
-							minion._mmode = MM_SATTACK;
-						}
-					}
-				}
-			}
+		return;
+	}
+
+	if (monster._uniqtype == 0 || (UniqMonst[monster._uniqtype - 1].mUnqAttr & 2) == 0)
+		return;
+	for (int j = 0; j < ActiveMonsterCount; j++) {
+		auto &minion = Monsters[ActiveMonsters[j]];
+		if (minion.leaderflag != MonsterRelation::Minion || minion.leader != i)
+			continue;
+		if (monster._msquelch > minion._msquelch) {
+			minion.position.last = monster.position.tile;
+			minion._msquelch = monster._msquelch - 1;
+		}
+		if (minion._mAi == AI_GARG && (minion._mFlags & MFLAG_ALLOW_SPECIAL) != 0) {
+			minion._mFlags &= ~MFLAG_ALLOW_SPECIAL;
+			minion._mmode = MM_SATTACK;
 		}
 	}
 }