The unspoken threat.
Mccallum's pathetic attempt to assuage China seems to indicate Canada is silently squirming to find ways to break the extradition treaty with the USA.
If Huawei's executive gets extradited, a Canadian will most certainly get executed.
I think, that is the unspoken threat - the sword hanging on Trudeau's head. With the election just a few months away.....that would surely cause a problem.