Sutra:
241. sharaNam.
242. upAyamAga.
243. indha sharaNa sabdham rakshithAvaiyum gruhaththaiyum upAyaththaiyum kAttak kadavadhEyAgilum ivvidaththil upAyaththaiyE kAttugiRadhu; kIzhOdE sEra vENdugaiyAlE.

Sri PBA Swami's Sarartha Deepikai:
The word "sharaNam" is explained as "being the means".

As in "upAye gruharakshitroc sabdhac sharaNamityayam vartate", the word sharaNam can point to the protector, the home and the means. But, here it is shown to have the meaning of being the means. Since it comes under the prior discussion of leaving all dharamas and seeking only Him as the means, this is the appropriate meaning for this word here.