You cannot cook the juices out during searing. You can cook the juices out by cooking too long whether you're at searing temps or not, but 'too long' being relative to your cooking temp.
The Maillard reaction (actually a series of reactions) happens more quickly at higher temps. The combinations of the amino acid components with the carbohydrates present combine, forming new components (many of which we identify and lump together as the aroma and flavor of searing or fond); these components continue to breakdown, recombine and reform as the process continues.
While there is a slight moisture loss when putting meat on a very hot grill or pan from an immediate evaporative effect, there is no more loss than would occur if the meat went on to a cooler grill or pan, it just happens quicker. A seared steak cooked to the same level of doneness as an unseared--or less seared--steak will have the same moisture content at the end of cooking (and lots more flavor, imo, because the Maillard reaction works more quickly at higher temps).
They key, of course, in searing is knowing when to slow the reactions by lowering the temp. If the reactions continue unabated, we get the flavor components most often identified as 'scorched' or 'burned'. A thinner steak cooked to rare, e.g., can be pretty much seared on both sides and removed from the heat entirely. A thick steak cooked rare is going to need to be seared and then moved off to a lower temp to continue cooking. Left at the high temp to cook one could certainly get it to rare, but the reactions, continuing all the while, would likely leave the steak tasting burnt.
Water activity inhibits the reactions which is why wet or marinated meat will take longer to sear than drier meat. The delay can be useful in some circumstances; dry your meat, or wipe off the marinade well, if you want searing to happen more quickly.