It wasn't until much later in active duty that he'd heard that his particular Engel had been used and reused in service as the pilots went slowly insane; after each new attunement, the beast had improved. Subsequent pilots remarked at how fast 'she' complied with their thoughts, to the point where young Mark began to think it was starting to predict his own thoughts before he finished them.
So here he was: a man hundreds of miles from his family and friends and removed from a girl he once knew (damned Mi-Go...), inside of an alien being (whom he'd named Gwendolyn because he didn't know of any feminine angel names) that was, according to his predecessors, 'thinking' increasingly human.
He thought a soothing greeting to the monster, and was given a response that had no words, but was indeed close to 'welcome.' After a few moments of companionable silence, both real and psychic, he idly began to stroke her walls; she answered with an emotion that seemed to incorporate 'that feels nice,' 'keep going,' and something else, instead of words, put him in the mind of an overlarge dog, simply wagging its tail. A sort of dialogue sprang between them. 'image of pilot, uninjured, healthy, content?' 'image of pilot, uninjured, healthy, okay. image of Gwendolyn, uninjured, healthy, content?' 'image of Gwendolyn, uninjured, healthy, content.'
Telepathic small talk does not translate well to speech.
A half-hour in which he, through a punch-drunk lack of sleep, tried to make small talk about the weather, food, and the other Engels passed. Over that half-hour, he was reminded that his Engel was indifferent to biting cold, that it was fed intravenously through a series of tubes, and that she had no real means of communicating other than through her pilot.