[quote=@EruditeAssassin]
I thought I had my actions in order.
[/quote]

In short it boils down to you either picking up and throwing the guard at the other guard, after beating the grapple attempt, or... avoiding the grapple altogether and striking with the pickaxe. You need adjust the rolls appropriately, for example, the pickaxe only critically strikes on a roll of 20 (not a sum of 20 or greater) and for two times its damage; thus a critical with the pickaxe would be 2d6+Strength modifier damage.