Firstly the match score is not a consideration either for this play or for any subsequent cube decision, as the players are a long way from the end of the match.
After playing 52, black will lead the race 102-107 (if he doesn't hit). With white on roll this will mean that the game is virtually even. The question is should black hit white's blot on his 11-pt and make one of his inside points by playing 8/3?
The potential gains are enormous. If white fails to enter, black will be very close to redoubling white out. If he enters without hitting, then black will have gained considerably in the race and will still have a strong attack.
The downside is that white may hit black's blot, when it will be white who has the edge. Indeed, if black stays on the bar long enough white can win a gammon. So would you rather be in a 50-50 race or in a position where 23 of white's next rolls are good for you and 13 (any 1 or 65) are bad?
I think it was fear of the gammon that made Winslow select the non-hitting play 10/5, 8/6. However, the right play is 13/11*, 8/3 and by quite a big margin - a bold move should most often be preferred to the "do nothing" move. Here Winslow left himself at the mercy of the dice when he could have taken more positive action and finished the game in a couple of rolls. Backgammon being backgammon he won the race easily!