His first instinct is to stay with her, but he trusts her - and anyway, someone needs to have her back.

And if that someone is him, then he's always going to be okay with that.

The first man gets a bullet before he even gets close enough to see what's happening - to the head, because Coulson has never enjoyed playing nice. And now as the smoke begins to thin out there are more of them: none of them too bright, admittedly, because they are making the classic hired-gun error of attacking a few at a time rather than all at once.

Well, good. At least this will give Nat some time.

(That barb about his agents stung. He hopes she makes this hurt.)