Something that could've happened during The Prestidigitation Approximation If Leonard hadn't run into the door. From the Perspective of Leonard.
"Penny wait" Leonard swiftly exited the entrance area. "I...I still want to be friends with you, I still..." he got caught in mid thought, trying to think of what to say next, to cover up what he was going to say.
"I know," said penny, her eyes softly staring into Leonard's, the two of them knew they were on the same page. "But Priya doesn't want me in your life, it's understandable"
"I guess...but it's not possible, you live across the hallway from me, you're everywhere..." god, he was making so many mistakes, why couldn't he get the right words out, he wasn't struggling with showing his emotions, he was struggling to keep them in.
"Listen Leonard, I know we see each other a lot, but Priya is jealous of my presence, and just wants us away from each other!" The last bit was a yell, Penny looked as if she was about to cry. Leonard was confused, but she was in her car and gone before he could respond.
He truly wanted to stay friends with Penny, and hang out with her even if Priya didn't know, but he was also scared of his feelings that he learned to dig deep inside of him. Last time those feelings broke his heart, and he did not want that to happen again. What confused him even more was why Penny. Why couldn't he have these feelings for Priya, but again deep down he knew Penny loved him more than Priya, and she fit with him, she fit with all of them, but specifically him. Priya doesn't fit, she's comfortable, and amazing, and exotic but she doesn't "fit" like Penny did.