Unless he can be smuggled out or airlifted, I can't see how he's going to avoid being arrested by the cops waiting for him. If he's planning to hand himself in, why not do it straight away?
They're probably in talks with the relevant UK government institutions. They talk about a new climate, and that "the plan is for him to leave as soon as the UK government decides to honour its obligations in relation to international agreements and calls off the siege outside - it's as simple as that."
What's there to talk about? He's wanted for questioning over sexual assault allegations. He doesn't get to have "talks" about that. He's not the messiah.
My immediate thought was suicide but I might be reading too much into his "soon".