Snell's law used in kinematics

So this is a kinematics question that my physics tutor has solved and uploaded on his YT channel. Link : https://youtu.be/dEmzWMnAnGc

I understand the solution, the way he has solved it, except one thing : In the diagram, θ > α clearly. Actually... if Q is the foot of perpendicular from H on AO, then at any point along QO, θ̂ > α

And for Snell's law to hold, θ̂ must be less than α, because u < v

So how can we apply Snell's law here if θ > α ??

Please clear it up, thanks a lot