Going back to Peeta hitting the force field, if that had happened after the bloodbath and they had to retrieve his body, how do you think Katniss would've handled watching a hovercraft take Peeta's body away?
Katniss would go absolutely feral, she would never let the Capitol take Peeta's body but I don't think it would even get to the point of the hovercraft coming for his body. If Finnick had been unable to revive Peeta then Katniss would immediately give up. She would either become catatonic, similar to her mother after her father died, or she would find a way to end her life, whether that is seeking out something dangerous in the arena or lashing out at Finnick in a bid for him to kill her. Probably the lashing out at Finnick when he tries to get her to leave because she will not be willing to leave him or accept that he is dead. Her job, which she literally says in canon, is to protect Peeta. If she failed she would not, could not live in that world. And she already knows that Snow isn't going to let her out of that Arena, with Peeta gone there is no purpose for her anymore.
Here are some fics that touch on this if you want to get a feel for what her emotional state would be if that happened, personally I think it would be alot like Silence. I only know of the one that addresses CF and the forcefield but if anyone knows another please let us know! And if anyone feels inspired to write a What if Peeta actually died from the forcefield? by all means proceed. I'm the worst aren't I?
Sorry for the delayed answer, I've been trying to find the time to get to this. For anyone else with an ask in my box expect answers this weekend; at least that is the goal.