@laughoutlood,
Here are the 3 clues and answers for the words that cross CARESS vertically:
15d = Fractures require rest periods. Answer BREAKS
8d = Taken aback on finding Lemony in snow vehicle. Answer STARTLED
9d = Luggage item in which to store diamonds, for example? Answer SUITCASE
That gives us the letters ?A?E?S.
22a = Pat tenderly provides medical treatment on ship. CARESS would therefore suit this clue.
Any alternative suggestions will be welcome.
Time to go to bed, will look at any replies in the morning.