We just need to put the "out" out of it and we get the exact meaning so that's what I did.
Don't get nervous... Stay calm, stay calm.Ah, speak of the Devil, it's Kyouko-chan.Idiot! Stupid! Die! You blockhead!!!H-H-hey, Kyouko...UwaaaaahYeah, it's true. Why?Why!?Is it true that you went out with Homura?
Wordplay on two meanings of "付き合う" (tsukiau) - "to accompany" and "to date (romantically)". Sayaka uses "romantic" meaning.Blockhead's so outdated!!I just went with her to the rooftop!Wordplay continues with Kyouko using "to accompany" meaning.