Unfortunately (or fortunately depending on the situation :)), the dynamic selector is designed to work like that (meaning to interrupt everything below it). Based on your tree design, you could probably add another condition on the right dynamic selector branch to also check a boolean variable like ‘isExploding’ and set the conditions to “ANY TRUE”. So the conditions will look like ‘if Distance < 15 to $Player OR $isExploding’.
Then of course you will also need to set that $isExploding variable somewhere (probably next to the ‘Self.Explode() action task).