Focused by turret but not getting attacked

Well, 2 games ago, on a ranked game i had as my enemy on bot tahm-kench, well i was pushing their turret with my teamate and i attacked tahm-kench under turret, he swallowed me and my teamate was attacking him under turret while i was in his mouth, and the turret was focusing me, but it wasn't attacking me(i wasn't taking damage) and so, my teamate kept attacking tahm-kench till he spat me out of his mouth way from the turret

Tell me if this is a bug or that's just how it works