Fixes race conditions when spawning

[keeofkoo]

📝 Description

Fixes #8

🎯 Proposed Changes

• Bug fixed

🧪 How Has This Been Tested?

• Test A: cargo test --workspace passed.
• Test B: reproduce the scene and it works as expected.

🏁 Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.