It's a combo heartwarming and funny that Tom finally has the prototype for his "Jump to Conclusions Mat".
After Peter accepts the consequences of his actions he admits to Joanna that even if he can't be happy with his job, he can be happy with his life as long as she's part of it. Awwww.
Along similar lines, Peter's protective of his friendship with Samir and Michael. He's the one who got a raise, but still puts himself on the line to try to get money for them. When they screw it up, Peter's also willing to take all the responsibility to get them off the hook.
Peter trying to save the remains of the vaunted red Swingline in the post-fire salvage scene also arguably qualifies.