The TEI was the most critical burn of the flight, as any failure of the SPS to ignite would strand the crew in lunar orbit, with little hope of escape.
ðə tˌiːˌiːˈaɪ wʌzðə mˈoʊst kɹˈɪɾɪkəl bˈɜːn ʌvðə flˈaɪt, æz ˌɛni fˈeɪlɪɹ ʌvðɪ ˌɛspˌiːˈɛs tʊ ɪɡnˈaɪt wʊd stɹˈænd ðə kɹˈuː ɪn lˈuːnɚɹ ˈɔːɹbɪt, wɪð lˈɪɾəl hˈoʊp ʌv ɛskˈeɪp.