Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
intrō-rumpo, rūpi, ruptum, 3, v. n., to break or burst into, to break in, enter by force: in aedis, Plaut. Mil. 2, 5, 50: quod ea non posse introrumpere videbantur, Caes. B. G. 5, 51, 4: cerva in cubiculum Sertorii, Gell. 15, 22, 9.