I assume
Vasile would be well aware of the fiasko that was the battle at Varna in 1444,
which was organised by the Pope supposedly to defeat the Ottoman, but in fact
was treason on the part of the Pope, resulting in a defeat of the combined
Christian army.
So the next Hungarian king, after the Polish - Hungarian king,
Władysław (also Vlad) III who apparently was killed at Varna (but may have
escaped to father Christopher Columb), being aware of that trap, outsmarted the
Pope rather than fall for the same trick. Importantly, the Varna was lost
because the Pope promissed to block the Turkish army at the Bosphorus sea
passage using the venetian shipping. Instead, he ordered the venetians to help
transport the turkish soldiers across to Europe. So now that we know that the
Pope wanted to combine with the Ottoman against the common enemy, the orthodox
church, the Vlad may have been saved by a smart Hungarian king....
..By
the way, impaling was extensively practiced in that and later period in battles
at the eastern flanks of the Polish kingdom, later Polish - Lithuanian
commonwealth, in wars against Tatars, Russians and lawless hordes who became
eventually Ukrainians (after the unification by Chmielnicki).