He worked (and travelled) alone, so would meet Fox, his friend, when their itineraries combined. They did so, as we know now, on far too many occasions. Yes, it looks very, very weird. That Werritty had a job as a global networker is even odder: you don't see these vacancies advertised very often in The Economist.
But the test remains: was there wrongdoing? For it to be corrupt there would need to be a commercial interest — and Fox's allies are clear that there was none. All this lies with the outgoing permanent secretary, Sir Gus O'Donnell, who is conducting a joint investigation with the MoD's permanent secretary, Ursula Brennan. They aim to report by next Monday.
UPDATE: The conspiracy theories about Werrity are escalating. Channel Four news has tonight claimed that he offered to "secure arms supplies" for Sri Lankans. A bold claim to make, especially given that the source was anonymous. My understanding is that Werrity has almost zero knowledge about the defence industry, so that sounds utterly implausible.