I got the impression that it was Martin ( the guy Tyreese didn't kill) who was watching Carol & Daryl, while staying hidden in the woods before the opening titles rolled. So apparently he was tracking down Rick's group. Plus when it was revealed that Martin, Gareth and a couple of Termites survived and were also the ones who kidnapped Bob, we see Martin wearing a black hoodie. B/c the guy that knocked out Bob wore a black hoodie. If Ty had killed Martin when he had the opportunity to. The Termites might not have caught up to Rick's group that early. But those in Rick's group who didn't want to eradicate all the termites are also to blame, imo. You'd think they learn by now after the chaos and death inflicted by the Gov or even Andrew, when both found another opportunity to attack 'em, b/c most of Rick's group made the same mistake they made before in last weeks ep.