I think “considered” is probably doing a lot of heavy lifting there. I’m pretty sure someone came up with it, maybe even Boris, and then he repeated it a bunch of times in front of semi-relevant people in a jokey-jokey way followed by an “…unless?”
I imagine nobody with any level of responsibility in actually producing such a raid considered anything apart from how to most politely say no to the prime minister.
There used to be a Twitter account called The Strange Log which regularly posted things like this. Looks like it’s inactive now, though.