Queries regarding Visa interview

My interview is scheduled on 12th June. I wanted to know that should I refrain myself from mentioning any plans for permanent residency in future? My masters course is research focused and quality doctoral research in the same field is only available in Germany. Will VO be able to gauge this aspiration of mine? I am very confused what to do? Don’t want to loose my chance because of silly mistakes.

Yes absolutely. Just tell them you want to return back to India and work here.
About your research related query. I dont think this will be a problem. The VOs are generally from normal background who have a surface knowledge about academics. I am sure they will have to do a lot of reading just to figure out whether this particular phd research is done in Germany only. Nonetheless, avoid any answers which indicates you are looking to stay after your course