diff --git a/OpenRA.Mods.Common/Traits/Mobile.cs b/OpenRA.Mods.Common/Traits/Mobile.cs
index c9b0022e6c..fba438ae69 100644
--- a/OpenRA.Mods.Common/Traits/Mobile.cs
+++ b/OpenRA.Mods.Common/Traits/Mobile.cs
@@ -117,7 +117,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		public readonly string SubterraneanTransitionSound = null;
 
-		[Desc("Can this unit fly over obsticals?")]
+		[Desc("Can this unit fly over obstacles?")]
 		public readonly bool Jumpjet = false;
 
 		[GrantedConditionReference]
diff --git a/mods/ts/rules/defaults.yaml b/mods/ts/rules/defaults.yaml
index 4fa94512f7..1e71a9e6f4 100644
--- a/mods/ts/rules/defaults.yaml
+++ b/mods/ts/rules/defaults.yaml
@@ -326,6 +326,7 @@
 		Damage: 2
 		DamageInterval: 16
 		DamageTypes: ExplosionDeath, TriggerVisceroid
+		RequiresCondition: !inside-tunnel
 	Guard:
 		Voice: Move
 	Guardable:
@@ -660,6 +661,7 @@
 			Tiberium: 100
 			BlueTiberium: 100
 			Veins: 100
+		TunnelCondition: inside-tunnel
 	WithTextControlGroupDecoration:
 	SelectionDecorations:
 		Palette: pips
@@ -888,6 +890,7 @@
 		Damage: -2
 		DamageInterval: 16
 		Terrain: Tiberium, BlueTiberium
+		RequiresCondition: !inside-tunnel
 
 ^DamagedByVeins:
 	DamagedByTerrain@VEINS:
@@ -895,6 +898,7 @@
 		DamageInterval: 16
 		DamageTypes: BulletDeath
 		Terrain: Veins
+		RequiresCondition: !inside-tunnel
 	LeavesTrails@VEINS:
 		Image: veins
 		Palette: player
@@ -904,3 +908,4 @@
 		MovingInterval: 16
 		StartDelay: -1
 		SpawnAtLastPosition: false
+		RequiresCondition: !inside-tunnel
diff --git a/mods/ts/rules/gdi-infantry.yaml b/mods/ts/rules/gdi-infantry.yaml
index 3dd0867c7c..fda836f149 100644
--- a/mods/ts/rules/gdi-infantry.yaml
+++ b/mods/ts/rules/gdi-infantry.yaml
@@ -106,6 +106,8 @@ JUMPJET:
 	-TakeCover:
 	Hovers:
 		RequiresCondition: airborne
+	DamagedByTerrain:
+		RequiresCondition: !inside-tunnel && !airborne
 	ProducibleWithLevel:
 		Prerequisites: barracks.upgraded
 	Targetable: