Yes, but the point in this case is that we are told the person did not have diplomatic immunity.
Not everybody who works at an embassy has diplomatic immunity.
The Geneva Convention dictates who gets diplomatic immunity, and that is based around your job description and rank.
This is not the first time either that the US has flown somebody out of the UK in questionable circumstances before they were questioned by UK police.
The UK is not a third-world country, there is no reason why somebody should not be questioned by UK police or dealt with in UK courts.
You can also bet your bottom dollar that if the tables were turned and the equivalent happend on US soil, there would be little chance of being flown out covertley. Most sensible people don't like "One rule for US, another rule for everyone else", even more so under the present US administration.