I never said it'd be romantic, quads-senpai. Maybe something more like Hunk and Lance's mermaid adventure. It's true I'm a filthy Pancefaggot, but I'm just thinking of what would hurt Lance the most:
Lance was already whining about Shiro favoring Keith over him, and this will be the final nail in that coffin. Hunk did a little bonding with Keith after the Galra reveal, and Hunk is Lance's best friend. If Hunk sides with Keith when Lance throws a bitch fit and challenges Keith, that would send Lance over the edge. Allura also accepted Keith already, and I can't imagine her leaving the castle to go after Lance anyway.
That really only leaves Keith himself or Pidge to go fetch him. If Pidge does what I think she might do and feed Keith his own words, she becomes the prime candidate to go help Lance get over himself while Keith and Allura figure out how to deal with the remaining Galra threat.