It’s unusual to have an ambush that has been so comprehensively announced in advance. Fortunately, to help unravel it we happen to have a transcript of the top secret radio communications that preceded this ambush:
UK: Maybot here. We’re coming through the Chequers Pass.
EU: Don’t come this way. We have a big force, 27 strong, blocking the way. We can’t let you pass through here.
UK: No, we have to go through here. If we turn back our own rearguard will shoot us.
EU: We don’t want to attack you, but the Chequers Pass leads into dangerous territory. We can’t let anyone through.
UK: Maybot, approaching Chequers Pass.
EU: There are multiple other passes. Please take one of them.
Warning shots are fired.
UK: Ambush! Treachery!