[Now that pained look doesn't just look like a headache; his expression flattens back out quickly this time.]

It's not that I was crazy...

[He doesn't even consider it, though Subaru's thought process makes sense. Something new to grapple with. He doesn't want to blame anything but himself.]

It's like I told you. I did it because I wanted to...

[...] But I...

[He considers not saying it at all.]

...I tried to stop it. I did, and I...didn't...at the same time...

It couldn't be stopped...