There had been a split second, right when he'd kissed Eobard, that Hartley was certain he'd made a horrible error of judgment. That Eobard was going to push him away and tell him to leave. Be angry with him for overstepping. Or, worse, gently but sternly tell him that he was flattered but couldn't reciprocate his feelings. But that didn't seem to be the case as Eobard kissed him back.
The reciprocation made it easy for Hartley to lose himself in the moment, deepening the kiss before finally breaking away and trying to remember to breathe. Wow. That had actually happened. Oh god. That had actually happened. He'd actually kissed Eobard. He stood there, shocked for a minute, his hand coming up almost unconsciously to touch his mouth.
"I'm sorry," he said, a little panicked though he tried his best not to show it. "I shouldn't have...that was...I'm so sorry." He couldn't help the instinctive reaction that any overt display of his sexuality would be received negatively.