I thought the whole toebox on my left (front foot) reactor would fall off when a 2" crack opened it up on the first run of the day, my last day out. I wasn't about to get off the snow on such an otherwise great day, so with caution I rode on. two runs later, a similar crack opened up on the right (rear) boot.
wtf, I rode, albeit pretty conservitively, on until closing, ready for a 'release' at any time that never came.
Now I'm not saying that your boot is good to go, but if you follow through with the "t-nut" repair and "fin-tech" heel, you'll probably be alright so long as you keep a close eye on it to see if it gets any worse.