Let a situation develop. It is basically when some shit had gone down and no one is sure what to do, rather than debate what to do, you just let it develop. Given a bit of time there will be a remedy.
Dave and Steve had just been discussing the fact Steve had shagged Kev's bird and Kev had found out. Steve was panicking. Steve said "Jesus Christ, what the fuck am I going to do Dave?" Steve said " I don't know, just let it develop"