Whilst quinine sensitivity is definitely plausible, the amount of quinine derived from tonic water, which is strictly controlled and in significantly reduced quantities compared to historic tonic water, would require a person to drink in excess of 20 litres per day just to reach therapeutic levels. It is highly unlikely anyone could consume so much tonic water constantly.
There is no separation in the limo and House does not have a weapon. The actor he was abducting should have just strangled him.
House is doing a visual field exam on guest star Jason Lewis, whom he thinks has a brain tumor, without patching one eye, testing both eyes together at the same time. Visual field exams have to be done one eye at a time, with the eye not being tested wearing a patch, to prevent one eye's visual field from interfering with the measurement of the other eye's visual field. House doing the test without an eye patched will yield worthless information.