Solution:

Place $B = (0, 0),$ $C = (14, 0),$ $A = (5, 12),$ so $M = (7, 0)$ and $AM = \sqrt{4 + 144} = 2\sqrt{37}.$ By power of the point $M$ in the circumcircle, $MA \cdot MP = MB \cdot MC = 49,$ so $MP = \frac{49}{2\sqrt{37}}$ and extending $A \to M$ by that length gives $P = \left(\frac{567}{74}, -\frac{147}{37}\right).$ The direction of $\overrightarrow{BP}$ is proportional to $(27, -14),$ and the direction of $\overrightarrow{CP}$ is proportional to $-(67, 42).$

Write $Q = (5 + 2t,\ 12 - 12t)$ for $t \in (0, 1),$ so that $AQ = t \cdot AM.$ Using $\tan\theta = \frac{|u \times v|}{u \cdot v}$ for the angle between rays, $$\tan\angle PBQ = \frac{394 - 296t}{222t - 33}, \qquad \tan\angle PCQ = \frac{1182 - 888t}{370t + 99},$$ and the second numerator is exactly $3(394 - 296t).$ Setting the two tangents equal cancels this common factor and leaves $370t + 99 = 3(222t - 33),$ so $296t = 198$ and $t = \frac{99}{148}.$

Then $AQ = \frac{99}{148} \cdot 2\sqrt{37} = \frac{99}{148}\sqrt{148} = \frac{99}{\sqrt{148}},$ and since $\gcd(99, 148) = 1,$ the answer is $99 + 148 = 247.$