Can I just say (and I know next week I could totally be proved wrong) but I don't believe Kate or Steve are bent.
We have to remember that Steve had his fingers half cut off (and he finally got redemption for that tonight), was thrown in jail, Lindsey was killed in his car, he was then thrown down the stairs by Balaclava man. Kate had to witness all that done to her bestie, was also attacked by Lindsey, chased Dot down the street with a machine gun and was almost shot, watched Ted get arrested, knew she was working with Ryan who had almost cut Steve's fingers off.
If I were them, I'd have an emergency plan as well. Seeing as they seem to have the most dangerous jobs in the country I don't blame them for having a locker with some burner phones in and be the only people to know where each other are. Crikey if I were them think I'd have him put a GPS in my arm I'd be running round paranoid af