Unsportsmanlike conduct can be a lot more than just arguing. My opinion is that 2 vs. 5 really isn't a huge deal in the game's situation at the time it happened. At that point, Lucic simply needed to be removed from the game, and he was. That the roughing was 2 minutes instead of 5 isn't really a big deal the way I see things. Maybe I'm just biased though. With the time remaining I'd probably just thrown him a 2+10 (and recorded it as "head contact" to keep it simple) then used the 10-minute misconduct as a reason to send him to the dressing room and not need to file an incident report.
Admittedly kind of a lazy approach.
