Part time people are not these poor little people on half the salary. They are on the same salary, but work half the hours. Hour per hour, they're on the same.
Why people get pissed off, is in incidents like this, when all the full time people (earning the same hourly rate) end up pulling their weight far more. It's the full timers, at 5pm who always end up with the "we need to stay until this is done" and working til 7pm, while the part timer walks out at 4pm because "that's when they finish" and is never there at the end of the day when the problems happen.
Here, OP gets her fill of food, then sits there with this "I'm ok, Jack" attitude. You lot are hungry, and having to meet a deadline, but I've eaten and going home before the problem is fixed.
The full timers being paid hour by hour, the same as OP, are the ones that have to forgo their food. That have to get the job done. OP couldn't give a toss. She's there for her lesser hours, not a team effort. And they have picked up on that. That will be what the "report" about her will be. Hence the mention of "part time."
No one's calling in HR over today's incident alone. This will be a backstory of them being sick of her shit.