OOC WMG: The guards' reaction to seeing Charon, "shit they're back!" , makes me think they've dealt with mutants before...
I'm seeing 3 options here:
1) The original guards of the facility included mutants
2) These are the original guards, and the individuals that attacked the facility were mutants
3) These guys have encountered mutants before in some other fashion. Maybe they're anti-mutant guys? Maybe something else?
You guys have any other crazy conspiracy theories?