Clark didn't know what was going on. One second he was standing there with a big old grin on his face, eager to greet Chloe into the new world that, unfortunately, she was also trapped in. The next? He appeared to be terrible, terrible confused. She was going to kill him? Wasn't that a little harsh - even for someone like Chloe? What had he done? "Uh, Chloe?" She looked angry. Beyond angry. Clark even took an unintentional step back out of worry that Chloe might try to strike him. It was kind of a silly thing to do since Chloe couldn't even hurt him - not unless she was carrying kryptonite - but Clark did it anyway. There was just something about that angry look on her face that always made Clark want to hide behind a curtain until she calmed down again.
Clark stepped back until he found Raven. If anything, Chloe would be hesitant around Shelby.