LONDON — Eugenie Bouchard could have lost her focus after the fourth game of her Wimbledon semifinal Thursday, when play was delayed for five minutes during Simona Halep's medical timeout for a left ankle injury. Bouchard also could have gotten sidetracked when action was halted again, smack-dab in the middle of a tiebreaker, because an ill spectator was being attended to in the Centre Court stands. And everything really could have unraveled for Bouchard later, as she let match point after match point slip away.