As Niiai has already said, the rule book look out sir rule is outdated. This is the current rule :
LOOK OUT, SIR
Models cannot target a unit that contains any CHARACTER models with a Wounds characteristic of 9 or less with a ranged weapon while that CHARACTER unit is within 3" of any of the following:
A friendly unit that contains 1 or more VEHICLE or MONSTER models with a wounds characteristic of 10 or more.
A friendly non-CHARACTER unit that contains 1 or more VEHICLE or MONSTER models.
A friendly non-CHARACTER unit that contains 3 or more models.
In all cases, if that CHARACTER unit is both visible to the firing model and it is the closest enemy unit to the firing model, it can be targeted normally. When determining if that CHARACTER unit is the closest enemy unit to the firing model, ignore other enemy units that contain any CHARACTER models with a Wounds characteristics of 9 or less.
Goonhammer has a nice coverage of look out sir :
https://www.goonhammer.com/ruleshammer-look-out-sir/
The astropath is protected by pask, when he is within 3", and he is not the closest visible enemy unit. Pask is a character, but with more than 9 wounds, he protects the astropath. If pask would have 9 or less wounds, he wouldnt protect the astropath.