How quickly could her thighs knock me out if she wrapped them around my neck? Would there be any chance of escape?

I used to do BJJ and really depends where the thigh's are placed. If it's blocking your wind pipe, 15-30 seconds normally, give or take for you to lose conscious. if it blocks the carotid arteries, instantly to 5 seconds is how quick it would be to lose conscious. Just google ''How to escape triangle choke'' and you'll find your answer