I am a native Hungarian speaker. Literally "beülni" means "to sit in", which can be used for some different meanings, for example when somebody sits into the car, then we say "beül az autóba".
And when we say "beül egy filmre" it means 'he/she sits in(to the cinema to watch) a movie'
So it is just a sentence which is perfect in the spoken and written Hungarian language, and when we try to translate it, it sounds odd in English and I honestly don't know which verb would be better than 'go see'.
How about literally, "No, I am not sitting in for a boring film." We can say that in English and people would know what it meant. They would think in terms of staying in at home to watch it rather than going to the cinema. Is that how a Hungarian would view the sentence? There's no mention of going anywhere, no use of the verbs látni or nézni although I do realize, (and how!!) that literal translations don't always work terribly well from Hungarian to English.