The classroom of the Army Special Forces Underwater Operations School on Fleming Key is filled with the memories left by graduates, some of the most elite soldiers and commandos spanning all branches.

"Time will pass, will you?" reads the Sharpie-scribble on the clock.

A plaque on a wall reminds students in profane terms to disregard sympathy and to "get your mind right."

The school has one of the most physically and mentally arduous courses in the military, Lt. Col. Steven Basilici told the room Thursday afternoon. Basilici was at the base as the training cadre said goodbye to outgoing commander Maj. Craig Milliron and welcomed incoming commander Maj. Samuel Kline. A class was also on hand, and behind them their broad-shouldered instructors.

The training cadre takes any comers, which often includes not only Army Special Forces -- also known as Green Berets -- but Navy SEALs, Air Force Special Operations Forces, Marines and a host of other allied nations' elite soldiers.

"This is the most extreme and most dangerous," school offered in the Army, Basilici said, "and offers the absolute best our nation has to offer -- those who are the embodiment of the warrior ethos. For the men here, extreme accomplishments are the norm."

Kline comes to Key West by way of the University of Kansas, where he just completed his graduate degree in international and interagency studies.

Like nearly all the instructors and command staff at the base, he is a graduate of the diver course and a combat veteran with medals from Afghanistan and Iraq.

"I've been here six weeks already, working with Maj. Milliron and the staff, and it is an honor to return as a commander," Kline said.

The Philadelphia native and husband of retired Navy Lt. Cmdr. Heather Kline wants to continue the vision that Milliron and former commanders have for the post, including the much anticipated painting of the 50-foot dive tower and multimillion-dollar base improvement projects such as new boat facilities.

"The interagency cooperation here is very important," Kline said after the change-of-command ceremony, referencing the cooperation the base has with nearby Coast Guard Sector Key West and Naval Air Station Key West.

"The seeds have be planted, and we need to continue to make sure they grow," Kline said.

In a unique farewell, the instructors presented outgoing commander Milliron with the guidon, or small flag that symbolizes the unit.

The guidon is never allowed to touch the ground or be captured by enemy forces, and it's considered an honor to be its guardian.

When in battle, soldiers historically rally around and behind the guidon.

Typically, outgoing commanders are thrown in the training pool by the instructors, but weather Thursday forced the ceremony indoors.

"Words cannot express how I feel," Milliron said as he departed.

"This community truly treats us as teammates."

alinhardt@keysnews.com