Well then the Tardis must provide that function to any time Lord given the Master regenerated inside as well. But then when Melanie Pond regenerated in that alleyway the Tardis was nowhere in sight (probably not even on the same planet or the same time)?
If I understand it correctly Timelords have some kind of symbiotic bond with their Tardis....which will surely reach across time and space? So maybe it´s not about beeing near or in a Tradis, but actually beeing "bound" to one? Mel was concieved inside the Tardis, so maybe that´s her excuse?
But lord knows where the Master's Tardis was, or if it even still exists. Plus (although strictly speaking she didn't regenerate) there's Jenny to add into the mix.