Have I ever mentioned that I really like Ed’s character? It’s great how he develops because early on he can be really selfish and only concerned with his own goals. See the Marcoh encounter:
So Marcoh opens up to the two brothers about the Philosopher’s stone and how it was used in Ishval. He emphasises that it was a massacre that he feels responsible for.
He’s not interested in hearing about Marcoh’s guilt or the war or anything. He’s just after the stone. (Also Marcoh deserted the military, Ed. He doesn’t care about your cool title.) At least Al’s being more sympathetic, giving some encouraging news about the situation in Xenotime.
Ed meanwhile, breaks down a wall and finds the incomplete Philosopher’s stone. Basque Grand then comes in and confirms that the stone was used in Ishval to augment their abilities, allowing them to cause far greater destruction.
...That’s one of his stranger expressions. A still picture doesn’t really do it justice as you can’t see how his eyes are twinkling. Ed’s very excited to be getting some answers and he’s ignoring all the warning signs. Because this is the biggest break he’s had in almost 4 years of searching for the stone. Wars aren’t anything to do with him; he’s only here for the stone and they’re finally getting closer to it.
It’s pretty Ironic that instead of a flashback of Ishval while Marcoh’s talking, we get shots of the destruction in Liore - something that’s very much to do with him despite his ignorance.
A moment later, he does finally show some anger.
...But it’s because of Grand denying him access to Marcoh’s research about the stone. (Because no one cares about Ed’s cool State Alchemist title.)
Then Grand sends in soldiers to arrest Dr. Marcoh and it’s finally apparent that Ed’s actions have unwittingly caused him harm - his actions do have consequences outside himself. By going here, he’s tipped the military off about Marcoh’s location.
And Ed finally shows some guilt and empathy. This time, he’s angry at himself. We even get a flashback to Nina and Ed’s inability to save her from the military’s clutches. He’s afraid he’s making another mistake.
He runs after the car, trying to make things right.
Exactly how far he would’ve gone to save Dr. Marcoh we sadly don’t find out as that’s when Scar appears and suddenly they all have a different problem.