(Erik and Callisto standing in the back 'cuz nobody gave them a hug.
Not that they wanted one. Didn't wanna feel like part a family anyway.
S-stupid X-Men. Don't like them or anything.)

Given the last time Betsy went up against a dangerous serial killer it ended with her getting her eyes gouged out, maybe leaving the fight to the fella with the healing factor and unbreakable bones is the sensible choice.
Even if his win-loss record against Sabretooth is shaky at best.