I don't think that's quite the same, he knew what Raiden could do, and that he could tank it.
Here he's fighting a literal magic wizard, think facetanking might be something he'd be a tad more cautious of, especially because he should know about the existence of wild dudes like mantis or the sorrow due to his government standing given he knew about the patriots.
So is it not safe to assume he sent them as far away as he could then if he was lying?
In which case-
He has WAY better movement speed compared to them, they were forced to fight it looks like, but Armstrong not only shreds every enemy that can be tossed at him, to the point theyre not even a threat, he an do so while moving. If they were forced to fight, that'd eat up time, and if they couldn't escape, that'd eta up time, and then just traveling would eat up time. Armstrong himself can literally dash at mach speeds. If it'd take them 24h just to go Point A to Point B without any intervention, Armstrong would take like not even a hour comparatively.
Mind you, he'd have to do that before Armstrong lands 4 hits on him still.