I guess it depends on whether your drama teacher knows the text well, if they do, discussion would be a good thing because you are exposed to an alternate viewpoint which can assist you to formulate a more well-rounded and insightful viewpoint about the text. However, bear in mind that whatever theme/analysis you extract from a film must be firmly related to the module you are studying, always focus on the module rubric and any particular essay question you are given when you are analysing visual texts, do not just analyse visual texts in isolation. However, whenever possible, I would still advise you to discuss your viewpoints with your English rather than your drama teacher, since the demands of English and drama are slightly different. Hope this helps