Flashback to 33 minutes ago...
So, when exposed to a frequency of 33.742 GHz, the crystals glow, which means... what?
"Rrrgghh!" Rodney McKay's frustrated grunt rang out in the empty lab. He had been working on these 'memory crystals' for about 30 hours straight. He really should have gone to bed eight hours ago, but, after some intensive translating, he found that they were not, in fact, memory crystals associated with storing computer memory, but actual people, much like the Asgard do. He also found that there were over ten-thousand crystals in a hidden alcove of the laboratory, yet they all seemed to be empty.
"Damnit." He said, to nobody in particular. He had been hoping that the Ancients had left some of their number behind, along with a cloning facility, as a much more efficient form of suspended animation. He looked over the table, observing the crystals he had tested during the day. They were clear, about thirty centimeters long, as wide as a beer can, and had eight sides, being flat on either end. He tried to think of the whatever-gon name that pertained to it, but couldn't get his brain to work properly. He groaned pathetically.
After groaning several more times, to no avail, he decided that he needed coffee. The high-caffeine stuff. The real McCoy. The only – "Dah!" he exclaimed, jumping backwards into the Frequency Generator, causing it to emit a particularly strong pulse at exactly 33.742 GHz.
As it turns out, Dr. Beckett had been standing over him for a few minutes now, and, not expecting such a reaction, Carson jumped as well, off to the side, where an inadvertently placed memory crystal was knocked to the floor, glowing brightly for a moment before shattering on the hard floor.
In a series of events that could only be described as syzygy, both Carson and Rodney were positioned exactly between the Frequency Generator, and the Memory Crystal, which was overloaded by the extremely strong pulse, sending out a neuronic wave that impacted Dr. Beckett, wiping clear his neural pathways, while imprinting them onto Dr. McKay's brain.
Several minutes passed before Rodney regained consciousness. He immediately ran to Carson, and, through no action of his own, began yelling crazily.
"What the hell!?" he said, between screams. He fought for control of his body, though it would not listen to him. He finally stopped screaming, but his eyes darted at himself, then raised his hands and turned them about in front of his face. Before he knew it, his eyes were locked on Carson's unconscious body, and an angry Scottish accent burst from his mouth.
"What the Sweet-Mary-Mother-of-God is going on!?! McKay! What's happened!?"
As the truth dawned on both Carson Beckett and Rodney McKay, their single pair of eyes went wide enough for the both of them.