If they were really going for P4 it is away from the terminal to the right
If I'm reading above chart correctly, P4 extends to the left of 10L too. If that is so, then they were indeed making a left turn into P4. Looks quite a tightish turn in slippery conditions. Might have been better to continue to N3.
Edit: In fact that left turn is N1. Missed that somehow.