Actually Eli does not seem to be as affected by pressure as some other QB's. not hat he likes getting hit, but he has a way of staying healthy even when he does.
Superhuman powers, primarily.
Point is, no one likes being hit. Eli doesn't shy away from contact; if he contorts his body -- a natural response -- then it's mainly only to buy some more time, or try to evade the rush to make a play downfield.