Sure, Tatsuo feels a surge of guilt, but mostly he gets angry. He's had to work really hard to not blame himself for what happened in October. And to have it dug up by these creatures gets dangerously close to undoing all of that. He clamps down on his emotions, refusing to let it use that memory against him.

"Hey, cut that out!"

Since that one didn't work, the creatures probe deeper, until they find other things. Things from his past life he's really not comfortable with. A man talking on a phone in a parking garage, turning around to suddenly get double tapped in the chest. Another man, on the ground in an alley, looking up at Ikuo... he gets shot too.