Reply To: Repeating Shemone Esrei without Tefilin

You are probably thinking of the Shittas Harashba brought down in the Beis Yosef (if I recall correctly) that for a Tashlumin the second Shmoneh Esrei must be while you are still Osek in that T’fillah, so it could be that as soon as you move on to Tachanun is too late.

I think that’s it. And I learnt it l’halacha, that’s how we act. Also, if it is necessary to say a second S”E for a missed tefila, as I recall it must be said immediately upon concluding the first S”E. Otherwise the opportunity is missed.