A little bit of playtesting with the interactive diagram it looks like the basic premise doesn't work out: It is not only possible but also advised to exchange one of the missiles by striking at your opponents missile. White is practically forced to follow this path, otherwise Black would get a free second strike. Black eliminates White second missile in the counter-strike.
It is also possible to eliminate a Royal piece using the missile strike (don't know if this is a good idea for the attacker since other pieces have higher fighting value).
A little bit of playtesting with the interactive diagram it looks like the basic premise doesn't work out: It is not only possible but also advised to exchange one of the missiles by striking at your opponents missile. White is practically forced to follow this path, otherwise Black would get a free second strike. Black eliminates White second missile in the counter-strike.
It is also possible to eliminate a Royal piece using the missile strike (don't know if this is a good idea for the attacker since other pieces have higher fighting value).