Contributed to the bevyengine/bevy repository by delivering two targeted improvements to the Bevy ECS system using Rust and entity-component-system principles. Addressed stability concerns by implementing safe command flushing and a despawn-guard for WorldEntityMut, ensuring that commands modifying entity state are executed in the correct order and preventing access to entities after they are removed. Enhanced event handling by refining the execution order so observers run before hooks during on_replace and on_remove events, resulting in more predictable lifecycle semantics. These changes improved test coverage, reduced undefined behavior during entity mutations, and contributed to a more robust game development workflow.