Large Language Models exhibit robust safety alignment when harmful intent is expressed in English, yet their resilience to code-switching and transliteration remains underexplored. This paper presents the first targeted investigation of code-switching as a safety failure mode, focusing on Roman Urdu—a widely used transliterated form common in informal and emotionally expressive communication. We introduce the Roman Urdu Adversarial Benchmark (RUAB), a semantically controlled evaluation benchmark designed to isolate linguistic variation from intent across four safety-critical categories: passive suicidal ideation, psychological distress, threat or intimidation, and coercion or emotional manipulation. Evaluating seven state-of-the-art models, we find that safety detection degrades consistently in code-switched and transliterated inputs, with the most pronounced failures occurring for passive suicidal ideation. Instruction-tuned and reasoning-capable models demonstrate greater robustness, suggesting these failures reflect alignment gaps rather than inherent model limitations. Our findings highlight transliteration and code-switching as under-recognized safety risks and motivate the development of linguistically inclusive, transliteration-aware safety methods.