Go to work in a nice suit. When it is time to leave for the interview, suddenly announce that you are sick, and leave. Then come back in 3 hours or whatever it is, saying you suddenly feel fine again.
They’ll probably can you, but it would be funny as hell.
I’m going to be not the dissenting voice, but a voice of caution. Yes it is fast food job and it may be somewhat “disposable”. However, keep in mind that even if this new place decides to hire you, it could be a week or two before you start working and up to another two weeks before your first pay check (which may be dismal depending on what days you worked during that pay period). Don’t piss your manager off by going AWOL or coming up with a terrible excuse because that’s going to mean a month of no paychecks for you.
If it were me, and I was on good terms with the manager, I would actually avoid the prospect of getting caught in a lie and tell the truth. Your manager knows that most of their employees are not going to be there forever. Turnover is very high in the fast food industry. What isn’t so high is honesty and commitment. I’m willing to bet that if you give your manager the respect of telling the truth, they will give you respect of leting you make up the time and stay on until this other place hires you.
If your manager is fine with this and lets you take the interview, return the favor by at least working out the remainder of your scheduled days at the restaurant. I’ve never worked for a fast food manager that actually expected a “two week notice”, but at least give them the courtesy of working your already scheduled days so they don’t have to bring in reinforcements and shift everyone’s hours around.
And, make sure you leave the restaurant on good terms. Thank the manager for the opportunity to work for them and tell them you’d love to work for them again if things don’t turn out at the new job. I quit a fast food job a couple of months ago to work at a new place that I thought I’d be at for a while. On my second night at the new job told me that they just realized they weren’t supposed to be hiring anybody new (I’d been “pushed through” the hiring process by a good aquaintance that worked at the company when they weren’t really supposed to be hiring anybody). I was let go on the spot, jobless again, with no one to turn to. Don’t burn bridges…you may need them again.
Curious as to how this turned out for the OP.