diff --git a/src/callback.rs b/src/callback.rs
index ca93abe..f19a898 100644
--- a/src/callback.rs
+++ b/src/callback.rs
@@ -78,15 +78,9 @@ where
             inner_system.apply_deferred(world);
             let mut runtime = world.get_resource_mut::<R>().expect("No runtime resource");
 
-            if R::needs_own_thread() {
-                runtime.with_engine_send_mut(move |engine| {
-                    Out::into_runtime_value_with_engine(result, engine)
-                })
-            } else {
-                runtime.with_engine_mut(move |engine| {
-                    Out::into_runtime_value_with_engine(result, engine)
-                })
-            }
+            runtime.with_engine_send_mut(move |engine| {
+                Out::into_runtime_value_with_engine(result, engine)
+            })
         };
         let system = IntoSystem::into_system(system_fn);
         CallbackSystem {
@@ -110,32 +104,21 @@ macro_rules! impl_tuple {
                 inner_system.initialize(world);
                 let system_fn = move |args: In<Vec<RN::Value>>, world: &mut World| {
                     let mut runtime = world.get_resource_mut::<RN>().expect("No runtime resource");
-                    let args  = if RN::needs_own_thread() {
+
+                    let args  =
                         runtime.with_engine_send_mut(move |engine| {
                             (
                                 $($t::from_runtime_value_with_engine(args.get($idx).expect(&format!("Failed to get function argument for index {}", $idx)).clone(), engine), )+
                             )
-                        })
-                    } else {
-                        runtime.with_engine_mut(move |engine| {
-                            (
-                                $($t::from_runtime_value_with_engine(args.get($idx).expect(&format!("Failed to get function argument for index {}", $idx)).clone(), engine), )+
-                            )
-                        })
-                    };
+                        });
 
                     let result = inner_system.run(args, world);
                     inner_system.apply_deferred(world);
                     let mut runtime = world.get_resource_mut::<RN>().expect("No runtime resource");
-                    if RN::needs_own_thread() {
-                        runtime.with_engine_send_mut(move |engine| {
-                            Out::into_runtime_value_with_engine(result, engine)
-                        })
-                    } else {
-                        runtime.with_engine_mut(move |engine| {
-                            Out::into_runtime_value_with_engine(result, engine)
-                        })
-                    }
+
+                    runtime.with_engine_send_mut(move |engine| {
+                        Out::into_runtime_value_with_engine(result, engine)
+                    })
                 };
                 let system = IntoSystem::into_system(system_fn);
                 CallbackSystem {
diff --git a/src/lib.rs b/src/lib.rs
index 2060054..173dda0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -315,8 +315,6 @@ pub trait Runtime: Resource + Default {
     type Value: Send + Clone;
     type RawEngine;
 
-    fn needs_own_thread() -> bool;
-
     /// Provides mutable reference to raw scripting engine instance.
     /// Can be used to directly interact with an interpreter to use interfaces
     /// that bevy_scriptum does not provided adapters for.
diff --git a/src/runtimes/lua.rs b/src/runtimes/lua.rs
index 59c1217..a049fbb 100644
--- a/src/runtimes/lua.rs
+++ b/src/runtimes/lua.rs
@@ -295,10 +295,6 @@ impl Runtime for LuaRuntime {
     ) -> T {
         self.with_engine(f)
     }
-
-    fn needs_own_thread() -> bool {
-        false
-    }
 }
 
 impl<'a, T: IntoLuaMulti<'a>> IntoRuntimeValueWithEngine<'a, T, LuaRuntime> for T {
diff --git a/src/runtimes/rhai.rs b/src/runtimes/rhai.rs
index 6718f95..57dd83a 100644
--- a/src/runtimes/rhai.rs
+++ b/src/runtimes/rhai.rs
@@ -204,10 +204,6 @@ impl Runtime for RhaiRuntime {
     ) -> T {
         self.with_engine(f)
     }
-
-    fn needs_own_thread() -> bool {
-        false
-    }
 }
 
 impl Default for RhaiRuntime {
diff --git a/src/runtimes/ruby.rs b/src/runtimes/ruby.rs
index 379e302..437ac23 100644
--- a/src/runtimes/ruby.rs
+++ b/src/runtimes/ruby.rs
@@ -505,10 +505,6 @@ impl Runtime for RubyRuntime {
             Ok(RubyValue::new(result))
         })
     }
-
-    fn needs_own_thread() -> bool {
-        true
-    }
 }
 
 pub mod magnus {