Browning reaction of santol fruit rind occurs immediately after opening. To illustrate, I gathered a semi-bangkok fruit. Sliced off portion of the rind and immediately shot an image. Subsequent images were taken every after 30 seconds up to 4.5 minutes, 10 minutes and 40 minutes.
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So if a good appearance of peeled santol is desired, control of browning reaction should be done as soon as the knife penetrates the rind. A two minutes lapse is forgivable but letting it brown for longer period is not.