It is a Sunnah of the Prophet, sallallaahu alayhi wa sallam, to enter the toilet with the left foot first, and it is also among his Sunnah to wear the right shoe before the left shoe, so how do I wear the shoes while inside the toilet?

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 is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

If the shoes are outside the toilet, or you can bring them out, then there is no problem as you may wear the shoes according to the Sunnah and enter the toilet according to the Sunnah.  However, if this is not possible, then enter the toilet with your left leg and put it on the shoe without wearing it, then enter with your right foot and wear your right shoe and then wear your left shoe; by doing so, you would have acted according to the Sunnah.

Allaah Knows best.