、。。
Oh, hang on a sec. My shoelace came untied.
Literal
Ah, wait time-out. Shoe [possessive-の] lace [subject-が] came-untied-[regret-ちゃった].
タンマ is a playful interjection meaning 'time out' — derived from reversing タイム (English 'time'). クツ (靴) and ヒモ (紐) are written in katakana for casual, playful effect. ほどける 'to come untied/undone' + ちゃった for mild dismay.