Yeah, the plotline was he trying to kill Goku before it exploded, but with "evacuate" wdym? Both Frieza and Goku say about Frieza wanting to "getting out of this planet"
He mitigated the blast because he was scared of getting in the explosion, but made it so there would be 5 minutes to beat Goku and then leave Namek
And Frieza points out to Goku that his spaceship was destroyed by Vegeta (talking about Goku having no way to escape), so Frieza wasnt taking about looking for a spaceship for himself
Lastly, Goku says that as Frieza said to be able to survive the vacuum of space, he should escape from the explosion, this obviously is by flying, else it makes no sense (Frieza also points out to Goku that he won't survive the vacuum of space when pointing out there's no spaceship, as if Goku can also fly away but wouldn't survive)
All that is said in the link I shared earlier:
https://imgchest.com/p/o24aorrreyl