I'd say yes, he probably could have taken him right there. However the reason there are always two Sith is because the master represents the power and the apprentice craves it. The apprentice probably could frequently "take" the master, but the apprentice hadn't learned all they could have from the master, so the master is still needed. At that point Anakin still needed the knowledge that Palps claimed to possess, so they both knew (at lease Palps hoped) Anakin wouldn't try to kill him them.
A fair fight might have been more of a toss up though. Remember Obi-Wan gets sent to fight Anakin, because he couldn't stand a chance against Palps. Then Palps doesn't move to help Vader until he's already wounded, that way he'd be less of a threat to Palps.
And of course if the apprentice tries to kill the master and instead gets killed themselves, the master picks a new apprentice.