What threats?, UK voted leave, why would EU want to prolong the process?
Because they are losing one of their biggest bill payers, investors and export markets. Do you think the other contributors to the EU want to suddenly pay the difference? Hell no, the UK even after rebates were a big payer and that extra money needs to be found from somewhere. The various mouthpieces will be knee-jerking all over the press for the next few weeks but the reality is that big business rules all and that big business wants this to be as smooth as butter.
The Germans in particular will want a smooth transition of trade deals considering the insane amount of engineering exports to the UK. The BMW and VAG boards would tear the German government a new one if knee-jerking costs them those billions.