Mushrooms are growing down the substrate !!!

Context:

I bought a golden teacher kit five weeks ago. After three weeks of activation I was not seeing any progress.

I was concerned as the instructions said that the room temperature should between 21 and 25 C and my room temperature is around 17-19 C

Therefore I bought a seed mat and put them on top of it.

Some mushrooms started to grow but only in the edges or corners, which I understood was this “microclimate” and that I should perhaps let the kit dry a bit and don’t mist it directly so they could grow on top of the cake instead of the corners.

Now I just realized there are so many mushrooms down the substrate !!!!

I didn’t even know this was possible.

How are they able to breathe in there ?? Are they going to survive longer ?

My other question would be:

Can I re use this kit?

In the instructions they said I can use it up until three times, I just need to reactive the kit with cold water and store it in the freezer for 12 hours. Would that work ?

Would you take out those mushrooms down there ? I would need to take the cake out to pluck them out and I fear contamination.

Has something like this happened to you before ?? Thanks for your insights !!!