Lucky it didn't go through, although central punctures are the best puncture to get if you have to get one!

Tyre inflation/sealer goop is awful stuff to work with, will make whoever is repairing the tyre hate you for using it... makes a huge mess of the rims (which doesn't usually get cleaned up internally, which can result in what was seen above) and can mess with the surface where the plug gets glued onto. If you can, swap on the spare, don't remove the screw & just take it in as is.