She doesn't much care about holding back impulse these days, or about stealth when she can simply defeat the enemy by overpowering them with blunt force.

So it's respect for John, and that alone, that makes Mercury decide to go along with it. Not that she'd put it in those terms, of course.

"I guess it doesn't matter if they live a few more minutes," was her response, on the assumption that stealth would slow her and the Chief down a little.