Blindes 1.5K/3K, 350 ante

Small tourney, around 30 players.

I get heads up against this guy. He's shown to be competent at the final table, i.e. capable of finding good spots for agression, but disciplined enough not to know to spazz / go out of line in bad situations. As I was chip leader with 6 left, I played relatively in line, yet he managed to 4b me twice. He might have had it, pretty credible spots in both cases.
My impression is that he's good (sizings, timings).

Now this hand is like 5 hands into the HU match, he has 45bb and I cover. Do you like the 4B? Do you like the shove? My impression is that many players like to go for click it back wars in MTTs, yet don't like to put the last bet in. I've encountered many times, and it's usually not cleverly done (put too much dead money too often IMO). I have no idea if this kind of weird stuff happens in HU ; I liked my 4b ingame, because his strategy seemed to 3b tiny a lot ; the 6bet felt marginal though.