Pike actually had no idea what had Jim so upset. The events surrounding Tarsus IV was not something that stuck out in Pike's mind. Back when it happened, he was in command of the Yorktown and rumors of the events on the planet circulated through the fleet, but nothing was ever confirmed.

"No, I don't and I'm not pretending that I do. You do."

He didn't want to tell Kirk he was on his way there, the last thing that he really wanted was to have him go off to hide somewhere else.