Performing the Sunnats before the Azaan is called out

If the awwal waqt for a salaah has come in e.g. asr, but the azaan has not yet gone in the masjid. If a person enters the masjid, will it be disliked at all that he reads his Sunnats although the azaan has not gone yet? If it is disliked, then would this be the case in a musallah that only gives 10 minutes between azan and salah, and a person would like to perform lengthy Sunnats and start before the azaan?