During the actual PCAT you probably don't want to get up from your seat unless you relax during your 15 minute break. As for the passage questions, according to these practice exams, you can still get a fairly high percentile score with a combination of 50% correct on the passages and 90% correct on the stand alone questions.
Remember, out of the 48 questions, 8 of them are experiment questions that Pearson is throwing in that don't count towards your score. Only thing is we don't know which 8 questions don't count.