If Panther were to hit on Krystal outside of the spacecraft it would be like the time of 0:03:00 to 0:03:11 of this SMG4 video
m.youtube.com/watch?v=4vCdvaE7… (the scene of High School Mario where Peach kicks Bowser in the crotch).
Fox's reaction to Panther hitting on Krystal would be exactly the same (even in voice) as Luigi's reaction to Fishy Boopkins talking to his dakimakura.