That wasn't a "carrier beam." Remember, everything that happened in that room was echoed/doubled. You'd see a person start to move, and then there'd be a second image that would be delayed by a beat before it started to move. You'd hear echoes when a person talked. And, by the same token, you'd see a phase pistol beam get fired twice.
I don't know if I agree with this. We see two separate beams, one skinny beam that actually hits Archer but doesn't harm him, then a secondary, much thicker beam rides on top of the first beam, and this is the one that Archer avoids.
First time I saw it, it reminded me of current tests to try and channel electric bolts with a carrier laser that ionises the way, creating a current path. Theoretically you could fire beams of lightning this way in the same style you see phasers work.