You can get a 200 in a LN even if you break your combo. Combo breaking 200s are pretty rare though.
To get one, you must press the LN with 200 precision, a combo break and a recover:
1) Press the start of the LN correctly within the 300 hitwindow (which is the same size as the one for a regular note). If the OD is 9 or higher, you must press with 300g precision in this part.
2) Release the LN early, before the hitwindow for a 50. This breaks the combo. The sum of the errors in milliseconds of the start and this release must be less than double the hitwindow for a 200.
3) Press again the LN, and release it within the hitwindow for a 50.
In the code, pressing a LN with 300 precision and a combo break also awards you with a 200 judgment, but that would only be possible if the OD was less than -2.5