Okay, but. This scene.

Shun reveals that his attacks on LDS weren’t just a result of tunnel vision, but that he actually had something of a plan, that he was comfortable could actually work out.

The whole plan is so telling about his family values (and how even Academia’s invasion hasn’t done much to change them probably). Shun knows at very least that Leo is somewhere far enough up in Academia to have the sway to release Ruri. That he is likely one of the people responsible for what happened to Heartland. Given that at very least Shun moves under the policy of sealing everything he defeats into cards, it’s probably not wrong to assume Resistance has their own fair share of “war prisoners” and trying to trade them against their own people has probably amounted to nothing so far. Yet his whole plan depends on the idea that Leo values Reiji enough to bargain him against Ruri and when Reiji corrects him on that, it tripped him up a lot.

Maybe that is because he was putting a lot of faith into that plan, but maybe also because Shun automatically assumes that all family loves each other and the idea that Leo – despite all the things he knows/suspects him responsible for – isn’t human enough to value his son enough to save him if taken, utterly catches him off guard.