I could go on for miles about why this argument about Allison "pushing Lydia around" tonight is complete and utter bullshit. Because if you think for a second that Lydia is weak enough to be pushed around, you are wrong. And if Allison had really wanted to take control of the situation, she would've put Peter on his ass a lot sooner than she did and she wouldn't have given much thought to it. Instead she took a step back when Lydia opted to talk to him; and she didn't do anything until Lydia made it obvious she was done speaking to him.
Allison had every right to be protective of her, not only because of what he did to her but because he killed Allison's aunt whom Allison loved. It was just as hard for Allison to be around him as it was for Lydia to be. And I think they both handled it beautifully.