If you're totally sure you don't need it, then just fail it.
Orrrrr.... you could adopt a positive mindset and try, if you can't get out of doing the subject. "then just fail it" - accepting this as an attitude/mindset has to be the worst way to prepare yourself for life outside of school. Sure, everybody fails at some stage, but it's how we respond to it that makes the difference. Did you try whatever was thrown at you, to the best of your ability? If so and you still end up not meeting the requirements, then OK. There are redemption processes in place that should then be taken advantage of to receive an S.
If the school is unwilling to withdraw you from the unit and they are making you wait until semester 2, which is the norm in quite a number of cases, then just get through it and try. End it on a good note.
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My advice to OP would be to see it through until the end of semester 1. Try everything, give it a real good go and if your best isn't good enough, then so be it. But at least you can walk away knowing that you gave it your all and didn't give up.
I redid my first and passed
This says you care - the fact you redid it and ended up passing rather than accepting failure. Keep this up.