Trois Park is a beautiful place to walk, enjoy this environment's best simulation of nature, and not think abut dreams. It's also, it turns out, a good place to run into strangers who wandered into those dreams. As much as Gaeta doesn't want to talk to anyone, he feels he owes it to her to apologize. After all, she did die.
"Martha Jones, right?" He's not interrupting, is he? He's probably interrupting. Maybe he should be somewhere that's not here.