Dhahhak (may Allah have mercy on him) says that if it is a state of war, or the enemy is pursuing him, or a wild animal is chasing him, then wherever he is facing, he should perform one rak‘ah at a time and perform bowing and prostration by gesture, and if even this is not possible, then he should say one or two takbirs.
Hadith Referenceسنن سعید بن منصور / كتاب التفسير / 412
Hadith Gradingمحدثین:سنده ضعيف جدًّا لشدة ضعف جويبر كما في الحديث [٩٣]
Hadith Takhrij«أخرجه سعيد بن منصور فى (سننه) برقم: 412، 2515، وابن أبى شيبة فى (مصنفه) برقم: 8354»