I forgot to mention, but to keep his shield and eyes also on the archer, Karvos will be attacking his back from an angle where it's more head on facing the carriage. The vagueness of my post could be read as just him swinging at the back of the head while rushing in from the side. This will cost Karvos a little more manuevering time, possibly a step or two.
Her being on the left ruined a straightforward attack coming from the side because his shield is on his left, so he'd be exposed to the archer. That makes this move more troublesome.