Stud 8/B board lock

[domester]

I'm relatively new to Stud 8/B and believe I've missed bets and raises when I have the best low hand. I obviously have board lock for low when I have, for instance, 5-4-2-6 and my opponent has 7-6-5-4. But what about my having 7-6-5-3 and my opponent having 8-3-2-A? If I have A-2 in the hole, my opponent can have me beat two ways (6-4 or 5-4 in the hole). So that can't be board lock, or am I missing something?