Is it permissible to step over people in the mosque during the sermon of the Friday prayer when there is no room in the back?

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Stepping over people in the mosque on Friday is disliked except in some cases where it is permissible without dislike.

First, if the Imaam cannot find a way to the pulpit.

Second, if one leaves his place to do something and then comes back.

Third, if one goes forward to fill a gap.

Fourth, if one does not find a place to sit as the case in question.