If a negative entry is a must, then he needs to be be able to verify he can easily clear on the surface. You can pre-press your ears on the surface if you are going in really negative to give you a jump start. Not really suggested as you can damage your ears and of course you should be trying to have a balanced rig so only negative 4-5 lbs to account for your breathing gas consumption (depending on what tanks you'll be breathing down). A few pounds over weighted isn't a big deal but you should always be able to fin up your rig if your inflator unexpectedly fails. A better idea is to have your captain drop you off a bit further up current to allow for a slower descent. If it is really a ripping current and you must hit the mark then I'd really consider not doing the dive. Nothing sucks worse than having to really fin hard to get back to a spot, getting stressed and burning up your gas.
That said, negative entries aren't that big of a deal BUT, you must be absolutely ready to descend once you roll off the boat. clear early and often and don't let your pressure build up to where it gets hard (or painful).